INFORMATION TO USERS
This was produced from a copy of a document sent to us for microfilming. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the material submitted.
The following explanation of techniques is provided to help you understand markings or notations which may appear on this reproduction.
1.The sign or “target” for pages apparently lacking from the document photographed is “Missing Page(s)”. If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure you of complete continuity.
2. When an image on the film is obliterated with a round black mark it is an indication that the film inspector noticed either blurred copy because of movement during exposure, or duplicate copy. Unless we meant to delete i copyrighted materials that should not have been filmed, you will find a good image of the page in the adjacent frame.
3. When a map, drawing or chart, etc., is part of the material being photo graphed the photographer has followed a definite method in “sectioning” the material. It is customary to begin filming at the upper left hand comer of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete.
4. For any illustrations that cannot be reproduced satisfactorily by xerography, photographic prints can be purchased at additional cost and tipped into your xerographic copy. Requests can be made to our Dissertations Customer Services Department.
5. Some pages in any document may have indistinct print. In all cases we have filmed the best available copy.
University Microfilms International 300 N. ZEEB ROAD. ANN ARBOR, Ml 48106 18 BEDFORD ROW, LONDON WC1 R 4EJ, ENGLAND 8100217
P a l m e r , L e o n G e o r g e
A SEARCH FOR CARBON AND M-TYPE STARS IN EIGHT GLOBULAR CLUSTERS
The Ohio State University Ph.D. 1980
University Microfilms Internationa! 300 N. Zeeb Road, Ann Arbor, MI 48106 PLEASE NOTE:
In all cases this material has been filmed in the best possible way from the available copy. Problems encountered with this document have been identified here with a check mark .
1. Glossy photographs ______
2. Colored illu stratio n s ______
3. Photographs with dark background ____
'4. Illustrations are poor copy ______
5. °rint shows through as there is text on both sides of page ______
6. Indistinct, broken or small print on several pages ______throughout
7. Tightly bound copy with print lost in spine ______
8. Computer printout pages with indistinct print t^--"
9. Page(s) ______lacking when material received, and not available from school or author ______
10. Page(s) ______seem to be missing in numbering only as text follows ______
11. Poor carbon copy ______
12. Not original copy, several pages with blurred type ______
13. Appendix pages are poor co p y ______
14. Original copy with light type ______
15. Curling and wrinkled pages ______
16. Other
University Microfilms Intemarional
300 \ 3 = E= »u. ANN A S30P VI1 •IS ’ 06 '3131 761-4700 A SEARCH FOR CARBON AND M-TYPE STARS IN
EIGHT GLOBULAR CLUSTERS
DISSERTATION
Presented in Partial Fulfillment of the Requirements for
the Degree Doctor of Philosophy in the Graduate
School of the Ohio State University
By
LEON G. PALMER, B.A., M.S.
*****
The Ohio State University
1980
Reading Comnittee: Approved By
Dr. Robert F. Wing
Dr. Eugene R. Capriotti
Dr. William M. Protheroe Adviser
Department of Astronomy ACKNOWLEDGEMENTS
I would like to express my deepest gratitude to my adviser, Dr.
Robert F. Wing, for his advice, confident guidance, and especially for allowing me to tap his seemingly unbounded store of astronomical knowledge. I would also like to thank Dr. Paul Byard for his help in putting together the image-tube camera and in the sometimes occult art of keeping it functioning. I also deeply appreciate the intellectual stimulus, knowledge and camaraderie I have have received from the faculty and students in the astronomy department. I feel I am finishing an exciting period, which was full of new ideas, new thoughts and new fro n tie rs. I must also acknowledge the people at Logicon, its heart and
soul, who helped me in ways too many to mention. Without th eir support during these last two years, finishing this dissertation would have been immeasureably more difficult. Lastly, I save my most loving thanks for my wife, Linda, who kept me sane, who gave me her unflagging moral support, who believed in me, and I thank her most for her love. Thank you again, my Linda, for spending those long nights working with me, for the weekends spent slaving over typewriters, computers and columnar pads. I owe you so much because you have given me so much. September 14, 1950. . . Born - Lindsay, California
1972...... B.A., Astronomy, University of California at Los Angeles
1974 ...... M.S., Astronomy, The Ohio State University, Columbus, Ohio. TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS...... ii
VITA...... iii
LIST OF TABLES...... v
LIST OF FIGURES...... vii
Section
1. INTRODUCTION...... 1
2. THE SURVEY PHOTOMETRIC SYSTEM ...... 7
3. CLUSTER PHOTOMETRY...... 34
4. ANALYSIS...... 147
5. SUMMARY...... 190
LIST OF REFERENCES...... 193 LIST OF TABLES
Table Page
1. Characteristics of the Filters of the Eight-Color System. . .11
2. Comparisons of Survey-System and Eight-Color F ilters ...... 16
3. Measured Characteristics of Survey F ilters ...... 21
4. Category 1, 2, and 3 Stars Used to Define the Response and Sensitivity of the Survey-System F ilters ...... 24
5. M Spectral-Type Calibrations for the Survey System and the Eight-Color System ...... 31
6. Metal Abundances for the Clusters Studied ...... 36
7. Survey-System Photographic Plate Log...... 44
8. 47 Tuc, Uncorrected Iris Readings ...... 54
9. OJCen, Uncorrected Iris Readings ...... 57
10. M5, Uncorrected Iris Readings ...... 61
11. M10, Uncorrected Iris Readings ...... 64
12. M12, Uncorrected Iris Readings ...... 68
13. M92, Uncorrected Iris Readings ...... 71
14. NGC 6397, Uncorrected Iris Readings ...... 73
15. NGC 6752, Uncorrected Iris Readings ...... 75
16. 47 Tuc, Corrected Iris Readings...... 82
17. M5, Corrected Iris Readings ...... 85
18. M10, Corrected Iris Readings ...... 88
19. M12, Corrected Iris Readings ...... 92
v LIST OF TABLES (Continued)
Page
20. M92, Corrected Iris Readings ...... 95
21. NGC 6397, Corrected Iris Readings ...... 97
22. NGC 6752, Corrected Iris Readings ...... 99
23. Photoelectric Survey-System Photometry of Globular Cluster S t a r s ...... 105
24. Calibration Equations to Convert Iris Readings to Magnitudes ...... 113
25. 47 Tuc, Photographic Survey-System Magnitudes and Indices . 115
26. M5, Photographic Survey-System Magnitudes and Indices . . . 118
27. M12, Photographic Survey-System Magnitudes and Indices. . . 121
28. M92, Photographic Survey-System Magnitudes and Indices. . . 124
29. NGC 6397, Photographic Survey-System Magnitudes and Indices ...... 126
30. NGC 6752, Photographic Survey-System Magnitudes and Indices ...... 128
31. Comparison of Photoelectric and Photographic Survey-System Indices ...... 137
32. Results of Analysis for the Globular Clusters ...... 175
vi LIST OF FIGURES
Figure Page
1. Eight-color photometry of representative late-type stars. . .12
2. Transmission curve for filte r A ...... 18
3. Transmission curve for filte r B ...... 19
4. Transmission curve for filte r C ...... 20
5. Differences between eight-color standard magnitudes (m3, m., and nv) and observed survey-system magnitudes (m., mB, and m-) for catagory 1 stars of different spectra? types ...... 26
6. Comparison of sensitivity of survey-system TiO index (TiO.) to similarly defined index for eight-color filter 3 (Ti 03)...... 28
7. Comparison of sensitivity of survey-system CN index (CNr) to similarly defined index for eight-color filter 4 (CN4) ...... 29
8. Sensitivity of survey-system TiO index (TiO.) to M spectral subtypes ...... 32
9. Schematic diagram of the S-l image-tube camera ...... 42
10. Finding chart for 47 Tuc ...... 46
11. Finding chart for 12. Finding chart for M5 ...... 48 13. Finding chart for M10 ...... 49 14. Finding chart for M12 ...... 50 15. Finding chart for M92 ...... 51 16. Finding chart for NGC 6397 ...... 52 v ii LIST OF FIGURES (Continued) Figure Page 17. Finding chart for NGC 6752 ...... 53 18. Density map of flat illumination plate ...... 77 19. Uncorrected filte r C iris readings (Ip) plotted versus filte r C pseudo-magnitudes (Pq ) for stars in M92 ...... 101 •ff 20. Corrected filte r C iris readings (Ip ) plotted versus filte r C pseudo-magnitudes (P q ) for stars in M92 ...... 102 * 21. Co£rect$d filte r A, B and C iris readings (IA , IB , Iq ) plotted versus photoelectric survey- system magnitudes (mA, mB, itIq ) for stars in M5 ...... 108 ★ 22. Cojrectgd filte r A, B and C iris readings (K , Ig , Iq ) plotted versus photoelectric survey- system magnitudes (mA, mg, iHq ) for stars in M12 ...... 109 ■k 23. Co£rect£d filte r A, B and C iris readings (IA , Ig , Iq ) plotted versus photoelectric survey- system magnitudes (mA, mg, iHq ) for stars in M92 ...... 110 ★ 24. Co£rect$d filte r A, B and C iris readings (IA , Ig , Iq ) plotted versus photoelectric survey- system magnitudes (mA, mg, itiq) for stars in NGC 6397. . . . Ill ★ 25. Cojjrect^d filte r A, B and C iris readings (IA , Ig , Iq ) plotted versus photoelectric survey- system magnitudes (mA, mB, [Hq ) for stars in NGC 6752. . . . 112 26. TiO/CN diagram for 47 T u c ...... 130 27. TiO/CN diagram for M5 ...... 131 28. TiO/CN diagram for M12 ...... 132 29. TiO/CN diagram for M92...... 133 30. TiO/CN diagram for NGC 6397 ...... 134 31. TiO/CN diagram for NGC 6752 ...... 135 32. Survey-system color-magnitude diagram for 47 Tuc ...... 140 33. Survey-system color-magnitude diagram for M5 ...... 141 v ii i LIST OF FIGURES (Continued) Figure Pa9e 34. Survey-system color-magnitude diagram for M12 ...... 142 35. Survey-system color-magnitude diagram for M92 ...... 143 36. Survey-system color-magnitude diagram for NGC 6397 ...... 144 37. Survey-system color-magnitude diagram for NGC 6752 ...... 145 38. A versus B diagram for 47 Tuc. Raw iris readings from first pair ofplates ...... 149 39. A versus B diagram for 47 Tuc. Raw iris readings from second pair of plates ...... 150 40. A versus B diagram for 47 Tuc. Averaged raw iris readings ...... 151 41. A versus B diagram for 47 Tuc. Corrected iris readings from first pairof plates ...... 152 42. A versus B diagram for 47 Tuc. Corrected iris readings from second pairof plates ...... 153 43. A versus B diagram for 47 Tuc. Averaged corrected iris readings ...... 154 44. A versus B diagram for **>Cen. Raw iris readings from first pairof plates ...... 155 45. A versus B diagram fo r^C en . Raw iris readings from second pairof plates ...... 156 46. A versus B diagram for«C en. Averaged raw iris readings ...... 157 47. A versus B diagram for M5, raw iris readings ...... 158 48. A versus B diagram for M5, corrected iris readings ...... 159 49. A versus B diagram for M10, raw iris readings ...... 160 50. A versus B diagram for M10, corrected iris readings .... 161 51. A versus B diagram for M12, raw iris readings ...... 162 ix LIST OF FIGURES Figure Page 52. A versus B diagram for M12, corrected iris readings .... 163 53. A versus B diagram for M92, raw iris readings ...... 164 54. A versus B diagram for M92, corrected iris readings .... 165 55. A versus B diagram for NGC 6397. Raw iris readings from first pair of plates ...... 166 56. A versus B diagram for NGC 6397. Raw iris readings from second pair of plates ...... 167 57. A versus B diagram for NGC 6397. Averaged raw iris readings ...... 168 58. A versus B diagram for NGC 6397. Corrected iris readings from first pair of plates ...... 169 59. A versus B diagram for NGC 6397. Corrected iris readings from second pair of plates ...... 170 60. A versus B diagram for NGC 6397. Averaged correctediris readings ...... 171 61. A versus B diagram for NGC 6752, rawiris readings ...... 172 62. A versus B diagram for NGC 6752, corrected irisreadings. . 173 x 1 INTRODUCTION Globular clusters are important testing grounds for our understanding of stellar evolution. Metal 1 ic itie s vary sig n ifican tly from cluster to cluster while carbon, nitrogen and oxygen ( CNO ) abundances differ among stars in the same cluster. CNO variations within a cluster are illustrated most clearly by wCen, which contains carbon stars (Harding 1962; Stock and Wroblewski 1972; Dickens 1972; Stock and Wing 1972; Wing and Stock 1973; Bond 1975), M stars (Dickens, Feast, and Lloyd Evans 1972; Feast 1973; Glass and Feast 1973) and weak G-band stars (Norris and Bessell 1977). The metal-rich cluster 47 Tuc shows CNO abundance variations in the form of a range of CN strengths for giants and subgiants (McClure and Osborn 1974; Bell, Dickens, and Gustafsson 1975; Hesser, Hartwick and McClure 1977; Hesser 1978; Norris 1978; Norris and Freeman 1979; Norris and Cottrell 1979). Norris and Cottrell (1979) also report that CN strength may be related to G-band weakening. Both primordial CNO abundance differences and changes caused by nucleosynthesis and mixing are probably required to account for the observed abundances. These CNO abundance variations are most readily revealed by the presence and strength of various molecular bands in the spectra of the red giant and subgiant sta rs. Some abundance differences have been determined from atomic lines in the hotter stars but this requires much higher spectral resolution than studies of molecular bands. The most prominent molecular bands in the red giants are those involving carbon, nitrogen and oxygen, the elemental and isotopic abundances of which can change significantly during a star's evolutionary lifetime. The presence of M stars (which show TiO bands) in globular clusters is c o rre la te d with o v erall clu ster metal 1 ic itiy . The metal-poor clusters contain few, while M stars are numerous in metal-rich globular clusters such as 47 Tuc (Feast and Thackeray 1960). The cluster«oCen is anomalous; although its giant branch extends only to about spectral type K4, as is normal for a metal-poor c lu ste r, i t also contains several M stars that are well displaced from the giant branch in the HR diagram (Glass and Feast 1973). There is evidence (Mould and McElroy 1978; Mould, Stutman and McElroy 1979) th a t TiO band s tre n g th , nominally temperature-sensitive only, is also sensitive to metal abundance. However, more work is needed to c larify the effect since relatively few globular clusters are known to contain stars cool enough to show TiO bands. Carbon stars are fairly common as field objects but extremely rare in globular clusters. At present only three carbon stars have been found in«oCen and two in M22 (McClure and Norris 1977 ; Hesser and Harris 1979). Because the sample is small, it is difficult to relate the presence of carbon stars to other cluster parameters such as metal 1icity. The ratio of C to M stars is not uniform throughout the galaxy. In the galactic nucleus, the C to M ratio C/M is about 0.003, (Blanco 1965; Blanco, Blanco and McCarthy 1978) while in the anti-center direction it is closer to 1.0. The distribution of C stars shows a definite avoidance of the inner regions of the galaxy (Blanco 1965; Yorka and Wing 1979) and the more luminous C stars (spectral type N) appear to be associated with the spiral arms (Blanco 1965). These differences are probably due to age and metallicity variations for the different populations of the galaxy (Blanco, Blanco and McCarthy 1978). This variation is further illuminated by the studies of the C/M ratios in the Magellanic Clouds. McCarthy and Blanco (1979) found C/M = 2 for various regions in the Large Magellanic Cloud and C/M = 36.1 for the central regions of the Small Magellanic Cloud. The C/M ratio for globular clusters is undefined because of the small sample size of C and M stars in these objects. For these reasons, I have selected as my dissertation topic the design and implementation of a survey technique that can distinguish faint C and M stars from other stars in selected fields. Although the technique is one that could be applied to any region of the sky, I have limited this initial study to a selection of globular clusters. There are several reasons for this choice. First, each globular cluster contains a large number of stars which can be photographed on one plate. Second, because of the comparative ease of observing large numbers of stars, meaningful statistics for the occuffence of C and M stars can be acquired. Third, the luminosities, ages, and masses of the C and M stars found in this manner can be determined from a their positions in their cluster color-magnitude diagrams. The la st reason is particularly pertinent to C stars since the vast majority of known C stars are field objects whose luminosities are not individually known, and since no direct determinations of mass have been made for C stars. From a statistical study of their proper motions, Baumert (1974) found a large range of luminosities for C stars and pointed out the need for better distance determinations. 1.1 SEARCH TECHNIQUES Techniques that can be used to search for M and C stars in globular clusters fall into the following catagories: (1) spectroscopic or photometric observations of individual cluster stars, (2) objective-prism or transmission-grating slitless spectra of cluster fields, and (3) direct filter photography of cluster fields. Individual spectroscopic or photometric observations require large amounts of telescope time to obtain a reasonable sample of stars. Osborn (1971,1973), McClure and Osborn (1974), McClure and N orris (1974) and H esser, Hartwick and McClure (1977) u tilized the DDO photometric system in this way but found only one CH star out of 105 stars (in 15 clusters) for which observations were obtained. Objective-prism and transmission-grating spectra techniques (Wing and Stock 1973; Bond 1975) are better suited for survey work but have serious problems with the overlapping of spectra in cluster centers and th e ir ap p lic a to n s are lim ited to clu ster fringes where crowding problems are less severe. The la st technique, direct filte r photography, has advantages over the other two. Since resolution is limited only by the sizes of star images on the plates, stars much closer to the cluster centers can be observed. Through appropriate choice of telescope, plate scale, and exposure times, a sig n ifican t sample of stars can be measured. For these reasons I have chosen this technique as the most viable for my search for M and C stars in globular clusters. Pike (1978) has used this method to obtain photographic DDO photometry of the globular cluster M5. He also used an electronographic camera and his work constitutes a te st of the combined system. Pike found three stars which showed strong CN from the photographic DDO photometry but he notes that a spectroscopic observation of one of them by Zinn (1977) does not confirm the presence of strong CN. Pike's work also fails to confirm Osborn's (1971) earlier detection of two strong-CN stars in M5 using photoelectric DDO photometry. Pike concludes that his method is only marginally capable of detecting strong-CN stars in clusters like M5. Although Pike's results are disappointing, they do not demonstrate the ineffectiveness of direct photography through narrow-band filters in general, since the DDO f ilte r s are not ideal for this application. Part of the problem is that the DDO filters are designed for photoelectric photometry from which the DDO indices can be determined more accurately than from photographic photometry. Furthermore, the DDO filters measure the CN bands of the violet system instead of the stronger near-infrared ones. In addition, the blue spectral region is fainter and is cut up by lines and bands to a much greater extent than the infrared. The choice of f ilte r s for a survey must take these and other considerations into account and should result in a filter system optimized for photographic photometry. With an appropriate choice of filters, it should be possible to recognize M stars as well as C stars, and these strong-banded stars should be much easier to detect than the strong-CN K giants for which Pike was searching. 2 THE SURVEY PHOTOMETRIC SYSTEM In sections 2.1 and 2.2, I present the basis on which the survey filters were selected. Section 2.3 discusses the establishment of photoelectric standard stars and the measured sensitivities of the filters to the spectral features they are designed to measure. 2.1 FILTER SYSTEMS Photometric systems are generally designed to produce at least three quantities- a color index (or color temperature), a measurement of a 1 uminosity-sensitive spectral feature, and a reference magnitude for stars in a limited range of spectral type. For example, the UBV and uvby systems, which operate in the 3500 - 5500 K region, are useful for stars earlier than spectral type G since their Balmer discontinuities are easily measured and most of the light output for these types is in the ultraviolet or visual regions. In late-type stars these photometric systems suffer from major problems. First, most of the light output is in the near infrared. Second, the continuum in the 3500 - 5500 % region is strongly affected by atomic lines and molecular bands so that B-V and b-y do not relate well to spectral type. Third, the luminosity features that the UBV or uvby systems measure are not present. The DDO system, which operates in the same spectral region and is intended for use on G and K sta rs, does measure a lum in o sity fe a tu re (CN) in late-type stars, but it suffers from the effects of heavy line blanketing. Furthermore, the DDO system is unable to detect CN when TiO is present. An ideal system for classification of later spectral types should provide a color index free of atomic lines or molecular bands, measurements of the most important temperature- and luminosity-sensitive features, measurements of abundance-sensitive fe a tu re s , and a reference magnitude that will relate well to the bolometric magnitude. For M s ta rs the m olecular bands th at provide the most useful information are those of titanium oxide (TiO) since the subdivisions of spectral type M are defined by the strength of these bands. The first TiO bands appear at about type K4. These are the (0,0) bands of the tr ip le t oc and ^ systems at X = 5167 and 7054 % (Keenan 1963). These and other TiO bands strengthen in cooler M spectral subtypes since they are primarily temperature-sensi ti ve. Bands of vanadium oxide first appear at about M7 and are useful spectral criteria for the la te r M subtypes. Because of the great strength of the TiO bands throughout the M spectral types and their relative insensitivity to luminosity and composition effects, they are an obvious choice for the spectral feature to use in any search for M stars. Sharpless (1956,1966) demonstrated that the TiO and CN bands in M stars could be used for the two-dimensional classification for M stars. Population differences however tend to blur the relationship between CN strength and luminosity (Keenan 1963). White and Wing (1978) have established a CN-1 uminosity relationship for M supergiants,for which the population differences are minimized. Using the Wing eight-color system which measures both TiO and CN features, they have successfully produced two-dimensional classifications for supergiants. The choice of spectral feature for carbon stars is more difficult. Carbon stars were first recognized as a class by the presence of the Swan bands of C2 in their visible spectra. Other carbon compounds have been found in the atmospheres of these stars with C2, CH and CN bands dominating the visual and•near-infrared spectrum. Keenan and Morgan (1941) developed the C classification system using the strength of the sodium D lines to indicate temperature and the strength of the C2 bands to indicate carbon abundance. Baumert (1972) used the Wing eight-color system to examine the variation of CN band strength with color temperature and C spectral type. CN is also present to a lesser extent in K and M stars. In early M supergiants the depression of the eight-color f i l t e r 4 ( 8120 K ) can reach 0.2 to 0.3 magnitudes. Carbon stars have depressions that range from 0.3 magnitudes in filte r 4 upwards to 1.5 magnitudes. The CN bands are thus very useful for detecting carbon stars. The spectral region in which both CN and TiO are most clearly seen is the near-infrared. The infrared bands are generally stronger and blanketing by atomic lines is much less severe in the infrared than in the blue or visual regions. Furthermore, since M and C stars are relatively cool, most of their energy output is in the infrared. From these considerations I conclude 10 th at the infrared bands of CN and TiO are preferable to use for survey work. 2.2 FILTER SELECTION One particular photometric system which meets the criteria discussed above is the Wing eight-color system. The filters of this system, which have bandpasses on the order of 50 %, were chosen to produce a blanketing-free color index for G, K, M and C stars, measures of the principal infrared bands of TiO, VO and CN, and a reasonably blanketing-free infrared magnitude. Regions that appeared free of spectral features on spectral scans of 10 - 30 X resolution (Wing 1967) were chosen for the placement of continuum f ilte r s . The selection of TiO and CN filters was complicated by the overlapping of their respective band systems. The filters and their defining parameters are presented in Table 1. In Figure 1, eight-color data (reduced to a system of absolute fluxes per unit wavelength interval) are plotted against wavelength for a K giant, a carbon star, an M4 giant, and an early M supergiant. In each case the eight-color spectrum has been fitte d with a blackbody curve which yields the color temperature of the star and serves as a continuum from which the molecular absorptions are measured. Only two molecules, CN and TiO, are responsible for essentially all of the absorptions shown by all four stars in Figure 1; the effects of 11 Table 1: Characteristics of the Filters of the Eight-Color System. Filter Central Features Measured # Wavelength (A) 1 7120 TiO V(0,0) band. Contamination from CN = +3 sequence. 2 7540 Continuum filte r. No TiO, minor CN contamination. 3 7810 TiO, primarily the -/(2,3) band. 4 8120 CN = +2 sequence. Minor TiO contamination. 5 10395 Continuum filte r. Defines the 1(104) infrared magni tude. 6 10540 VO. 7 10810 Continuum, occasionally contaminated by the He I line at 10830 A. 8 10975 CN (0,0) band. a Ari HR 2591 I 1.0 Mag 5 6 78 . X Aqr M 4.1 11 CPD -57° 3502 M 1.5 lab 0.7 0.8 0.9 1.0 X (/tm) Figure 1: Eight-color photometry of representative late-type stars. The dashed lies identify the filters which formed the basis of the survey system (filters A, B, and C). atomic lines and other molecules are almost completely negligible. The spectra of the K giant and the carbon sta r, which lack TiO bands, are thus pure CN spectra, and they differ only in color temperature and CN strength. Filters 3 and 7 at 7810 and 10810 % are the best continuum points in the near-infrared spectra of carbon stars since they lie in regions of CN opacity minima. Filter 5 at 10400 % is somewhat depressed in carbon stars but seldom by more than 0.1 mag. In the M4 giant, the CN strength (best judged at filters 4 and 8) is much weaker than in the carbon star, and is similar to that of the K giant; new absorptions due to TiO have appeared, depressing filters 1 and 3. Since filte r 3 can no longer be used as a continuum point, this function is taken over by filter 2 at 7540 % which lies at a TiO opacity minimum, although it is somewhat contaminated by CN. The Ml.5 supergiant has the same features as the M4 giant except that the CN is stronger and the TiO is weaker. The blackbody continuua for the M stars in Figure 1 pass above the fluxes in all of the firs t four filters because they have been placed by the iterative procedure described by White and Wing (1978), by which a correction for the CN absorption at filter 2 is applied on the basis of the CN strength measured at filters 4 and 8. This correction is intended to uncouple the measured indices of TiO and CN strength and to render the color temperature independent of luminosity. The primary drawbacks in using the Wing eight-color system in the present application are (1) that the number of filters is too large to be used efficiently in a survey, (2) that the one-inch diameter f ilte r s available are too small for photographic work, and (3) that the narrow band passes of the eight-color filters were optimized for accurate 14 classification by photoelectric photometry and are too narrow for photographic surveys of faint stars. Wing and Stock (1973) pointed out th a t carbon stars can be recognized by measurements in filters 3 and 4 of the eight-color system alone. M stars are differentiated from carbon stars because TiO and CN have opposite effects on the relative brightnesses in filters 3 and 4. If a measurement in filter 5 is added, a useful color index becomes available and the effect of continuum slope can be removed from the comparison of brightnesses in filters 3 and 4. I decided that modified versions of these three filters could serve as the basis for establishing the survey system. The modifications included increased physical dimensions and increased bandwidths. The increased size of the filters makes them useful for photography, while the increased bandwidth reduces exposure times. This change in bandwidth is limited, however, by the need for spectral purity and sensitivity to the features measured. The design characteristics of these modified filters which define the survey system are: Filter A Continuum/TiO, central wavelength Aq = 7780 R, width &X = 100 R between half-power points. This filte r is depressed by TiO in M stars. In carbon stars and other spectral types it measures continuum. Filter B Continuum/CN, = 8120 R, * X = 100 R. The (3,1) band causes a large depression in carbon stars and continuum is seen in M stars. Filter C Continuum/I(104), Aq = 10400 R, = 230 R. Essentially a continuum filte r in carbon and M stars, it is also used to define an infrared magnitude 1(104). F ilte rs A and B are close in wavelength, minimizing the difference between the two filters arising from continuum slope. However, if only f i l t e r s A and B were used, a hot star would appear to have a CN depression. The third filter is combined with filter A or B to produce a color temperature to discrim inate between a hot star with a steep continuum and a cool star with CN. The design characteristies of the survey filters are compared to those of the corresponding eight-color filters in Table 2. The comparison is also illu s tra te d in Figure 1 which shows the features measured by both systems. As is evident, the survey filters are not identical to their corresponding eight-color filters and have different responses to spectral features. The physical and optical characteri sties for filters A, B and C were subject to both spectral and manufacturing lim itations. The spectral considerations were: Filter A Must be contained within the interval 7700 to 7850 ft. This entire interval is nearly free of atmospheric absorption. It is limited by the atmospheric A band on the short wavelength end and by the CN (2,0) band head at 7850 ft on the long- wavelength end. Fairly strong TiO absorption, primarily from the (2,3) band, is present, increasing shortward. A VO band, which may be Table 2: Comparisons of Survey-System and Eight-Color Filters. Filter Ac (ft) AA (ft) Tolerance in Ac Survey Eight Survey Eight Survey Eight and AA for survey Filters (A) A 3 7780 7810 100 40 + 15 B 4 8120 8120 100 50 + 15 C 5 10400 10395 230 50 + 30 17 present in very cool stars, degrades longward from 7850 ft. F ilter B Contained between 8050 and 8200 ft. This filte r measures the strong CN (3,1) band. There is very little TiO or VO in this region. The Na I doublet at 8183,8195 is present in dwarfs. Filter C Centered at 10400 ft to give the 1(104) mag. Width can be greater than that of the others without introducing contamination by spectral features. In particular, the filte r avoids P$ 10049 ft and He 10830 ft. VO affects the region longward of 10459 ft but is seldom present. Manufacturing limitations are set by costs which vary with the size of the filte rs, the bandpass, and the specified tolerance in central wavelength and band width. Two-inch circles are the largest standard size produced by Infrared Industries Inc., which made the first four sets of eight-color f i l t e r s . This size is ideal for use with the S-l image tube described in section 3.2 with its one-and-three-quarter-inch photocathode diameter. The filters that were delivered by Infrared Industries Inc. differ slightly from their design characteristics although they fall within the tolerances specified when they were ordered. Transmission curves for these filters are shown in Figures 2, 3 and 4 and their optical characteristics are summarized in Table 3. 18 JOO. -90 .90. 37.85 t SO- -SO -30 7 0 -70 60 60 6a 50 •50 40 4-40- 40- -30- so. Figure 2: Transmission curve for filter A. 19 -100 100 90 37.84 A\ 80 80 8107 K 70 70 7 0 60 50 50 50 -40 •40 40 30 AA = 115 K 20 y; cb '-*3 '-*3 Figure 3: Transmission curve for filter B. 20 100 ica :iao 10390 % so 37.85 %:8a. 7 0 - 70 70 60 , -6 0 - 60— SO -40- 40 A \ = 234 ft 00 - 20 MO Figure 4: Transmission curve for filter C. 21 Table 3: Measured Characteristics of Survey Filters. F i1 ter Ae (%) 4A (%) Peak Transmission A 7782 92 60 % B 8107 115 62 % C 10390 234 64 % 22 2.3 CALIBRATION OF THE SURVEY SYSTEM Since the new filters A, B and C measure the same spectral features as filters 3, 4 and 5 of the eight-color system, the calibration of the survey system was carried out by observing photoelectrically, with filters A, B and C, a selection of stars for which eight-color data was already available. In this way I could compare the characteristics of the survey filters to those of the corresponding eight-color f ilte r s entirely on the basis of accurate photoelectric photometry and avoid the greater observational noise that is introduced by the use of image tube and photographic plates in actual survey work. Section 2.3.1 discusses the equipment used in more detail. Section 2.3.2 details the calibrati on proceedure. 2.3.1 EQUIPMENT The calib ratio n observations were made in January 1978 with the Perkins 72-inch (1.8 m) telescope of the Ohio State and Ohio Wesleyan U niversities, which is located at the Anderson Mesa site of Lowell Observatory near Flagstaff, Arizona. The two-inch survey f ilte r s were mounted in the OSU single-channel photoelectric photometer. The choice of photometer was dictated by the large size of the filters, which could not be mounted in the standard photometers available at Lowell 23 Observatory. The f i l t e r wheel of the OSU photometer was remachined to take four 2-inch filters although only three positions were used. An FW-118 photocell (S-l photocathode) and pulse-counting electronics were used with the photometer. 2.3.2 CALIBRATION The calibration process for the survey filters required the establishment of a set of photometric standards and an examination of the system's response to the presence of TiO and CN absorption. For these purposes, I observed stars of the following three categories: (1) stars with little or no CN or TiO (types B, A, F, G, K), (2) stars with a range of TiO strength (MO to M6), and (3) stars with a range of CN strength (G and K giants and supergiants, and C stars). Stars of category 1 were taken from the list of 95 photometric standard stars defining the eight-color system. The eight-color standard stars have been tested for constancy and are well distributed about the sky. The standard magnitudes on the eight-color system, tied together by a decade of use, are given in Wing (1979) on an absolute flux scale. Category 2 and 3 stars were chosen from the lists of stars with existing, but unpublished, eight-color observations. The selected stars are liste d in Table 4. Instrumental magnitudes were corrected for atmospheric extinction and instrumental -to-standard-system transformation coefficents were 24 Table 4: Category 1, 2, and 3 Stars Used to Define the Response a Sensitivity of the Survey-System F i1ters. HD Category Spectral HD Category Spectral Type Type 17361 1 K1 III 18449 1 K2 III 23401 1 A3 IV 25642 1 B9 V 26630 1 GO lb 30739 1 AO V 38656 1 G8 III 40035 1 KO III 58946 1 FO V 69267 1 K4 III 74280 1 B3 V 85503 1 K1.5 III 96833 1 K1 III 102870 1 F9 V 103287 1 AO V 113226 1 G8 III 114710 1 GO V 127665 1 K3 III 130109 1 AO V 214680 1 09 1013 2 M2 III 5316 2 gM7 16058 2 gM3 18884 2 Ml.5 19349 2 gM3 23475 2 gMl 25025 2 MO III 37536 2 M2 la 38944 2 gMl 39045 2 M3 III 39225 2 M2 II 40239 2 M3 III 41429 2 M3 III 49331 2 Ml III 57423 2 gMO 60522 2 MO III 97778 2 M3 III 98118 2 MO III 101153 2 M4.5 III 102212 2 Ml III 209857 2 M4 218329 2 Ml III 219576 2 gM5 224062 2 gM5 5223 3 C 16115 3 C 17361 3 K1 III 18449 3 K2 III 19557 3 C 30443 3 C 34467 3 C 38656 3 G8 III 40035 3 KO III 57884 3 C 58364 3 C 58385 3 C 59643 3 C 60826 3 C 69267 3 K4 III 79319 3 C 85503 3 K1.5 III 96833 3 K1 III 113226 3 G8 III 127665 3 K3 III 223392 3 C 224959 3 C 25 determined using catagory 1 stars as standards. Since the central wavelengths of the survey f ilte r s A, B and C are nearly identical to those of eight-color f ilte r s 3, 4 and 5, the standard magnitudes for catagory 1 stars at f ilte r s A, B and C were in itia lly assumed to be identical to the eight-color standard magnitudes at filters 3, 4 and 5. How well the survey filters reproduce the standard values is shown in Figure 5, where the residual difference between the standard magnitudes and the magnitudes based on survey-filter observations are plotted against spectral type. No dependence on spectral type is found for catagory 1 stars, and the average residual for each f il t e r is +_ 0.015 mag., which is no larger than the expected observational errors for nights of typical quality. The result is that the fluxes given by Wing (1979) for catagory 1 stars need no adjustment and any of the eight-color standards may be used to reduce survey-system photometry to the absolute flux scale. Extinction and transformation coefficents calculated from category 1 stars were used to convert instrumental magnitudes for category 2 and 3 stars to standard survey-system magnitudes. Four quantities can be defined from the survey-system magnitudes in filters A, B and C. These are (1) the infrared magnitude 1(104), which is just the magnitude at filter C, (2) the color index A-C or B-C depending upon whether filter A or B better represents the continuum, (3) the TiO depression at filter A, and (4) the CN depression at filter B. Only three of these parameters are independent since the TiO and CN depressions are defined as the excess absorption filte r A compared to filter B or vice versa. The survey-system TiO and CN depressions are BO AO FO GO KO +O.OS 04 -O.OS Figure 5: Differences between eight-color standard magnitudes (m3, m4, and m5) and observed survey-system magnitudes (m., m^, and m^) for catagory 1 stars of different spectral 27 defined differently than their equivalent eight-color indices. The eight-color TiO and CN depressions are defined as the observed depressions at certain filters below a blackbody curve fit to the best continuum points as discussed in section 2.2 and illustrated in Figure 1. The survey system TiO or CN depressions are defined as the observed depression at filter A or B below a linear "continuum" fit through filter C and the better continuum point at either filter A or B. A more elaborate procedure does not seem warranted since it is impossible to measure separate TiO and CN indices when both molecules are present. Equations 1 and 2 present the survey-system index definitions: TiO = mA - mg - 0.149( mg - mc ) (1) CN = mB - mA + 0.130( mA - m^ ) (2) It should be noted that, because of the way that these indices are defined, only one index can be determined for a sta r. The other index is set equal to zero since it would otherwise have a negative value. The survey filters A and B have different se n sitiv itie s to TiO and CN than the eight-color filters 3 and 4 from which they were derived. I have examined these differences by comparing the survey-system TiO and CN depressions for category 2 and 3 stars to similarly defined eight-color indices for observations in filters 3, 4 and 5. The comparison is illu strated in Figure 6 for the TiO indices and Figure 7 for the CN indices. The slopes of the linear relationships in these figures indicate that filter A is 9% more sensitive to TiO in M giants than filter 3, while filter B is 22% less sensitive to CN than filter 4. The differences are attributable to the different bandwidths of the filters which include d ifferen t amounts of continuum and TiO or CN 28 TiO .2. Figure 6: Comparison of sensitivity of survey-sytem TiO index (TiO.) to similarly defined index for eight-color filte r 3 (TiOg). CN 4 Figure 7: Comparison of sensitivity of survey-sytem CN index (CND) to similarly defined index for eight-color filte r 4 (Cfl4). 30 bands. I calibrated the survey-system TiO index to give spectral types from observations of category 2 stars which have cla ssific a tio n s from 8-color photometry (Wing 1978). The eight-color scale of spectral types is ultimately based on the classifications of Keenan and Morgan (1973). The survey-system TiO indices for a number of M giants are plotted against their eight-color TiO indices and spectral types in Figure 8. The two indices are linearly related from Ml.5 to at least M4.5. The eight-color indices are numerically larger than the survey-system indices because filter 1 of the eight-color system measures a stronger band than does filter A of the survey system. The adopted spectral calibration for the survey system is given in Table 5 along with the eight-color calibration from White and Wing (1978). The survey-system TiO depression does not appear in giants before about Ml.5. This insensitivity of the survey-system to TiO absorption in late K and early M giants is caused by the presence of CN in these stars which depresses filter B below the continuum so that the TiO depression calculated from equation 1 is too small. It is not until about Ml that the TiO depression of filter A has grown stronger than the CN depression of filter B in the giants. M supergiants will show the same effect but to a greater extent because of their stronger CN, and their survey-system TiO index will not appear until a later spectral type than the giants. Therefore the survey-system M spectral-type calibration is sensitive to CN strength, and the calibration derived from Figure 8 is accurate only for M giants. The eight-color TiO index does not show the same effect because of the way Table 5: M Spectral-Type Calibrations for the Survey System and the Eight-Color System (unit = 0.01 mag.) Spectral TiO Depressions Type Survey System Eight-Color System For Giants All Luminosities MO 0 25 MO. 5 0 30 Ml 0 35 Ml.5 3 42 M2 7 50 M2.5 12 60 M3 17 70 M3.5 25 85 M4 33 100 M4.5 43 120 M5 53 140 TiO, 'A 10 MQ MftTM/ /n/.r Ml AIW M3 /10 TiO Figure 8: Sensitivity of survey-sytem TiO index (TiO.) to M spectral subtypes. 33 the eight-color continuum is defined (section 2.2). Beyond Ml.5 the relationship between the two TiO indices is linear, and the slope of the relationship indicates that the survey-system index is only 49% as strong as the eight-color index. This is understandable since the eight-color index measures a stronger TiO band than the survey-system index. This is illu stra te d in Figure 1, where the depression due to TiO in the M stars at the wavelength of filter 1 is noticeably stronger than the depression at the wavelength of filter A. Although the survey-system TiO index is less sensitive, it provides sufficent accuracy for classification since it would take a 0.1 magnitude error in the measurement of the index to shift the spectral classification by one subtype around M3. The final adopted spectral type calibration of the survey-system TiO index for giants is tabulated in Table 5. 3 CLUSTER PHOTOMETRY Observations of eight globular clusters on the survey photometric system have been obtained. Section 3.1 details the selection of the clu ste rs. The photographic equipment used for the survey is described in section 3.2, while section 3.3 describes the reduction of the photographic plate material. Section 3.4 presents photoelectric survey-system photometry in each cluster which is used to convert the photographic data to magnitudes on the survey-system. 3.1 CLUSTER SELECTION There are presently 132 known globular clusters in our galaxy and attempting to observe all of these is beyond the scope of my dissertation. However, a cross-section of these objects was selected for observation on the basis of the criteria given below. 34 35 3 .1 .1 SELECTION CRITERIA The primary selector! criterion was that the horizontal branch have a V magnitude brighter than 15.10 mag. This crite rio n was established so that the entire giant branch could be examined. Baumert (1974) found that the absolute magnitudes of field carbon stars encompass the range from the red giant tip to the horizontal branch; this suggests that carbon stars in globular clusters might be found in the same range. Exposure times with the S-l image tube camera (described in section 3.2) were limited by tube background to about 240 min., and this lim it was reached in f il t e r C by G-type stars of about V = 15.2. Seventeen clusters were found to satisfy this VHB limit. I established priorities among these clusters on the basis of other interesting properties such as presence of known C stars, known or suspected presence of M stars, or other abundance anomalities as well as the value of itself. The number of clusters for which I was able to obtain observations was limited to eight because of observing time constraints, weather, equipment problems and "the thousand natural shocks that flesh is heir to ..." (Shakespeare 1603). The main observing time constraint was imposed by the fact that most of the brighter globular clusters lie in the southern hemisphere, and only one observing run of 5 nights was available from a southern site. The eight clusters are listed in Table 6 along with their V^g and metal abundances. The metal abundances are expressed as [Fe/H] = log (Fe/H)cluster - log (Fe/H)0 36 Table 6: Metal Abundances for the Clusters Studied. NGC Name V Diam [Fe/H]* HB (') Alciano Kraft Zinn 104 47 Tuc 14.05 100 -0.52 -0.60 -0.64 5139 «*> Cen 14.5 110 -1.55 -1.60 5904 M5 15.10 58 -1.34 -1.10 -1.58 6218 M12 14.90 36 -1.52 -1.56 6254 M10 14.80 48 -1.47 -1.50 -1.70 6341 M92 15.10 34 -1.99 -2.20 -2.19 6397 12.60 88 -1.48 -2.00 -2.24 6752 14.00 70 -1.52 -1.70 -1.52 * Metal abundances according to Alciano (1977), Kraft (1979), and Zinn (1980). 37 and the sources for these values are noted in the table. 3.1.2 CLUSTER PROPERTIES Table 6 presents the gross metal abundances of the clusters I have studied. Some of the clusters have been well studied for abundance variations while others have not. A comprehensive discussion of abundance variations among globular clusters can be found in Kraft (1979). 47 Tuc (NGC 104) is one of the better-studied clusters. Its [Fe/H] of -0.64 (Zinn 1980) makes it one of the most metal-rich globular clusters. Its giant branch extends to spectral type M2 and it also contains several M stars of la te r spectral type (Feast and Thackeray 1960). There is a range of CN strength among stars on the giant branch, asymptotic giant branch, horizontal branch (Norris 1978; Norris and Freeman 1979), and subgiant branch (Hesser 1978). Bell, Dickens, and Gustafsson (1975) also report that "the N abundance may be enhanced by a factor of ten in some cases." This cluster provides an opportunity to test the ability of the survey system to detect and classify M stars and, because of the range in CN strength among its stars, the potential for the discovery of strong CN stars using the survey filters. Omega Cen (NGC 5139) appears to be a very metal-poor globular on the basis of metal abundance parameters derived from its color-magnitude diagram. Its [Fe/H] of -1.6 (Zinn 1980) was derived 38 from the integrated light of the cluster but it is misleading since the cluster contains stars with metallicities ranging from -2.2 to -0.8 (Kraft 1979). It was the first globular cluster found to contain carbon stars (Harding 1962; Stock and Wing 1972; Stock and Wroblewski 1972; Bond 1975), and a range of CN strengths has been found among its giant branch and asymptotic giant branch stars (Hesser et a l . 1977). It also exhibits variations in the strengths of Ca II and CO among its stars (Kraft 1979). The giant branch of « Cen extends to about K4 but the cluster also contains several M stars that are well displaced from the giant branch. The giant branch of Cen is unusually wide in the (V, B-V) diagram (Cannon and Strobie 1973) but is much narrower in the (V, R-I) plane (Morris and Bessell 1977), possibly due to the different effects of variations in line blanketing on the two filter systems (Kraft 1979). Omega Cen presented the certainty of detecting previously discovered M and C stars and the best potential for the discovery of new ones since it contains a very large number of stars and the central regions have not been well studied because of crowding. Most work on th is clu ster has been done in the cluster fringes. M5 (NGC 5904) is a moderately metal-poor globular with [Fe/H] = -1.58 (Zinn 1980). Osborn (1971) had suggested the presence of several strong CN stars on the basis of photoelectric DDO photometry but their presence was not confirmed by either Pike (1978) or Zinn (1977). Zinn does find mildly enhanced X 4216 and A 3889 CN bands in 8 of 38 giant-branch stars he studied. 39 M12 (NGC 6218) and M10 (NGC 6245) have not been studied very extensively. The clusters have [Fe/H] = -1.56 and -1.7 respectively (Zinn 1980). Hesser et al. (1977) have obtained DDO photoelectric photometry for seven stars in M10 but none shows exceptionally strong CN bands. M92 (NGC 6341) is extremely metal-poor with [Fe/H] = -2.19 (Zinn 1980). Zinn (1973) discovered that its asymptotic giant-branch stars have system atically weaker G-bands than subgiant branch stars of the same temperature. Carbon et a l . (1979) found a large range in carbon and nitrogen abundance at various places in the color-magnitude diagram with carbon depleted by a factor of 19 in asymptotic giant-branch stars and nitrogen enhanced by up to a factor of 10. However, no range in CN strength was found for M92 stars by Hesser et al . (1977), possibly because of the extreme weakness of the 4215 CN feature in metal-poor stars. NGC 6397 is a very metal-poor globular with [Fe/H] = -2.24 (Zinn 1980). Mai 1 ia (1977, 1978) and Norris and Zinn ( 1977 ) have found different G-band strengths on the asymptotic giant branch and indications of carbon depletion by factors of 3 to 10 in these stars. NGC 6752 is a moderately metal-poor globular with [Fe/H] = -1.52 (Zinn 1980). Mallia (1977) found no evidence of the blue CN bands in seven stars he studied. He did find several stars showing weak G-bands. In general, the more metal-rich clusters show large CN variations while the metal-poor clusters show none. Although the lack of detectable CN variations in metal-poor clusters may simply be the 40 resu lt of the extreme weakness of CN in these clusters, the metal-poor clusters do show variations in G-band strength, indicative of CH variations among their stars. Omega Cen, which appears as a moderately metal-poor cluster from its color-magnitude diagram, is the exception to the rule as i t contains carbon stars, strong CN stars, weak G-band stars, and M stars. 3.2 PHOTOGRAPHIC SUBSYSTEM 3.2.1 S-l IMAGE TUBE CAMERA An S-l image tube camera was used to obtain the direct photographic plates in all three filters, since the only emulsion with any se n sitiv ity in the one-micron spectral region is the I-Z emulsion which is extremely slow. Furthermore, no other commercially available image tube has a photocathode response beyond about 9000 %. Although other, more sensitive, detectors could be used for filters A and B, it was most e ffic ie n t for this program to use the same detector for all three filters. Two S-l tubes and support equipment were made available by Dr. Kenneth E. Kissell of the Wright-Patterson Air Force Base. The two-stage tubes are magnetically focused, have useful photocathode areas 1.75 inches in diameter and operate at a 20,000 volt p o ten tial. The phosphor screen of the tube used in the camera is coupled to a nitrogen-baked IIa-0 photographic plate with a 3-inch Aero-Ektar transfer lens. The photocathode is cooled with a two-stage cooler which consists of a thermoelectric cooler in direct contact with the photocathode and a circu latin g methanol fluid chilled to dry ice temperatures to cool the hot side of the therm oelectric cooler. The assembled S-l image tube camera is pictured schematically in Figure 9. Arrangements were made by Dr. Paul Byard of the O.S.U. Astronomy Department to borrow the equipment from Dr. Kissel!. The two tubes that were available were essentially identical in photocathode response with one tube (arbitrarily numbered tube 1) having a slig h tly more uniform se n sitiv ity . Tube 1 was chosen as the primary tube to use with tube 2 serving as a backup. The image tubes and th eir support equipment were tested at the 42-inch telescope at Lowell Observatory in June 1975. Tube 1 failed at this time, its one-micron response disappearing and overall sensitivity dropping rapidly from day to day. This tube was discarded and tube 2 was used for all subsequent observations. 3.2.2 PHOTOGRAPHIC OBSERVATIONS The globular cluster survey was scheduled to begin at Lowell Observatory in July 1975, but because of the failure of the filter manufacturer to deliver the filters, no observations were obtained at Offset Guider Filter SI ide / ■jj- Dark Slide Guiding Eyepiece Thermo-electric Cool Image Tube Focus Magnet Transfer Lens Plate Holder ure 9: Schematic diagram of the S-l image-tube camera. 43 that time. The observing program was delayed until June 1976 when good plates in all three filters were obtained for four globular clusters with the 42-inch telescope at Lowell Observatory in Flagstaff, Arizona. Plates for four southern globulars were obtained at Cerro Tololo Inter-American Observatory in July 1977 with the 60-inch telescope. The plate material is summarized in Table 7. The Lowell p lates, taken with the 42-inch at f/8, have 18 arcmin diameter field s while the CTIO plates, taken with the 60-inch at f/8, have 12 arcmin diameter field s. Each plate is centered on its cluster's center. Column 3 of Table 6 lists the diameters for the clusters (Peterson and King 1975) and in no case do my plates entirely cover a cluster. 3.3 PLATE REDUCTION 3.3.1 MEASUREMENT Good plate material was obtained for the globular clusters 47 Tuc, oo Cen, M5, M10, M12, M92, NGC 6397 and NGC 6752. I selected stars for measurement in each cluster on the basis of the color-magnitude diagrams and finding charts given in the following sources: 47 Tuc (Wildey 1961; Lloyd Evans 1974), wCen (Woolley et a l. 1966), M5 (Arp 1955), M10 (Arp 1955; Harris, Racine and De Roux 1975), M12 (Racine 1975), M92 (Sandage and Walker 1966), NGC 6397 (Woolley et al . 1961), 44 Table 7: Survey-System Photographic Plate Log. Cluster Filter Exposure Date Telescope Location time (min) 47 Tuc A 60 7-24-77 60-inch CTIO B 45 7-24-77 60-inch CTIO C 120 7-26-77 60-inch CTIO A 33 7-25-77 60-inch CTIO B 30 7-25-77 60-inch CTIO C 120 7-25-77 60-inch CTIO to Cen A 90 7-25-77 60-inch CTIO B 60 7-25-77 60-inch CTIO C 165 7-26-77 60-inch CTIO A 105 7-27-77 60-inch CTIO B 50 7-26-77 60-inch CTIO M5 A 120 6-18-76 42-inch Lowel1 B 120 6-18-76 42-inch Lowel1 C 240 6-23-76 42-inch Lowel1 M10 A 120 6-14-76 42-inch Lowel1 ■ B 120 6-16-76 42-inch Lowel1 C 240 6-16-76 42-inch Lowel1 M12 A 120 6-12-76 42-inch Lowel1 B 120 6-13-76 42-inch Lowel1 C 240 6-14-76 42-inch Lowel1 M92 A 145 6-17-76 42-inch Lowel1 B 120 6-17-76 42-inch Lowell C 300 6-17-76 42-inch Lowel1 NGC 6397 A 20 7-25-77 60-inch CTIO B 22 7-25-77 60-inch CTIO C 60 7-25-77 60-inch CTIO A 30 7-24-77 60-inch CTIO B 30 7-24-77 60-inch CTIO C 120 7-26-77 60-inch CTIO NGC 6752 A 90 7-27-77 60-inch CTI0 B 100 7-27-77 60-inch CTI0 C 105 7-27-77 60-inch CTI0 C 120 7-27-77 60-inch CTIO 45 NGC 67.52 (Alciano 1972). Additional stars in cluster centers were also selected. Finding charts for all the stars are presented in Figures 10 to 17. The finding charts were prepared from plates taken in filte r C. The scale, in arcmin, is shown on each chart. I used three different Cuffey iris photometers to make measurements of the star images on the plates. The ir is measurements are accurately reproducible and can be converted to magnitudes by establishing an iris-magnitude relationship for a photoelectric sequence in each cluster. The use of the different Cuffey iris photometers was dictated by my location at various times. The ones I have used are located at Perkins Observatory in Delaware, Ohio, at Kitt Peak National Observatory in Tucson, Arizona, and at the Department of Astronomy of the University of California at Los Angeles. The iris readings for selected stars in each cluster are compiled in Tables 8 to 15. 3.3.2 REDUCTION Photocathode sensitivity variation presented a major problem in the reduction of the iris photometry. This problem is illu s tra te d in Figure 18, which is a density map of a plate taken of a fla t field of illumination with the S-l image tube camera. This sensitivity variation results in stars of the same brightness appearing as images of different sizes. 45 **• w \» ' • *10 . T-i •30Z S5>30t, • - 52 •» ' " : V'.;3 307* j ; 30« «9 S v . mi. VO/. " 5#. : . i 307. . , - “ ' ^ 3* »jr7 * *• »«. ,#OT ** - V * . « • • . « • 3,r »**• \ •* -*^1 •33/ . • " j •'•*"■ <**//• • k •. . V *, > *«>«« > • . ;•'<»*» . * * » ‘ *io7 • V--J 101 >- • •looz* to-, *./!(? - f . • * • . » *• . . »i38P%«u * .-* 33H- • • ». > 3W /. ■ •* .*»,. 2 0 0 3 w * ‘• S S w l l i i J v» ,1,,s • Vt /l •v r .lo w . *••;■'* IS* * t •’ .Vfc •:•*• 3 4 0 #,M>V ^ .20052#o5 •'- ,W. -:-Vt'i.vU4'. :.;• ^ - - . .. « « • i *2oos • / ; ■ - ‘ 3% . *&«. •; # /j, . *2007 #2t7 37®* •** •R 3 ( • . 211 %KLi •2t>$ *»8b- :■:■!— — < flfc;«35f * 1 Figure 10: Finding chart for 47 Tuc. 47 M * >£U. fo* * "•V-» ' . '• --• ... //Ov, ’ • * /£>.* *. 0^ "* v ’ -*•.,' ■??) \ ///'. ^ _ v . - * . . . ^ .••-■* . V/^.5 Figure 11: Finding chart for CO Cen. 48 o . sooZ»i « • t *^001 j 11. \*50O3 • * %• . SooH \5 0 l3 * ' Figure 12: Finding chart for M5. 49 ioa$3r aobv1#*' •. 7^ # ' zo zW ' * S3*. « • 37. ^ . . iff- V3 * - *7 ril* • <(!• Z3» * 51 * * • & • * : 't V3«aip .. * --• ■.« v fix-V ‘1°. oc 20135' qa• 85* 35* ^ 2.013V v-$> 10IW roiM* • f . • £ Figure 13: Finding chart for M10. 50 <3*. [ Figure 14: Finding chart for M12. Figure 15 "Y S O .. * -3V7 H02‘ • 173!». * • > 4 3 W 3& ’ w S'3R9^ HZ0' 97?. “/W* * f<7/< V76. -W73 . rtV* 566* «?• 57Y- 903* 57?* -I 6/Z« 1' 4J». 6^ * 603 * Figure 16: Finding chart for NGC 6397. 53 •♦ --V •’ -V ••* ••* j,-. . . -r - ■•■ jij.tyst < .-; ' T .‘..-’'•-V^.,,'1>0^fV.-L, ■*-•’ *■ >f ‘ VjV'i ■v''T^I-A. ^.' V _-J, if«.S'i./.*rJ «"•. .iis: i«-f. , „ V w 70. *71 1' £< '>.;.: ■, Figure 17: Finding chart for NGC 6752. 54 Table 8: 47 Tuc, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Wildey (1961) and Lloyd Evans (1974) except for 99991 to 99993 which are identified on Figure 10. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 03 490. 490 . 550 . 410. 455. 575. 045 277 . 219. 245. 164 . 0 . 389. 052 402 . 374. 418. 293. 360 . 505. 055 360 . 321. 367 . 257 . 323 . 492. 090 254. 212. 352. 0 . 0 . 413. 092 337 . 299 . 362. 205. 25S . 484. 095 320 . 272. 309 . 198. 268 . 456 . 107 494 . 482. 553. 400 . 451. 600 . 111 278. 238. 257 . 178. 249 . 431. 115 505 . 485. 568. 398. 440 . 613. 139 400 . 375. 390 . 294. 362 . 528. 148 371. 336 . 351. 2S8 . 351. 511 . 149 231. 201. 223. 162. 224 . 404 . 162 240 . 203 . 239. 0 . 0 . 410 . 164 372-. 331. 344 . 287 . 348. 535. 186 364 . 328. 337 . 286 . 357 . 511 . 212 545. 543. 571. 440 . 485. 611 . 213 383 . 357 . 315. 280 . 350 . 46 4 . 235 323 . 281. 252. 213. 273. 411 . 237 450 . 432. 435. 341. 393. 511. 254 411. 422. 420 . 337 . 379 . 499 . 301 393. 357 . 422. 280 . 362. 529. 302 420 . 387 . 455. 303 . 374. 549. 306 355 . 312. 367 . 252. 325. 498 . 307 343. 295. 345. 226 . 306 . 475. 309 415. 377 . 429. 319. 377 . 520 . 310 310 . 267 . 294 . 222. 310 . 44 0 . 317 328. 273. 298. 224 . 294 . 440 . 318 410 . 389. 425. 325. 370 . 497 . 331 272. 178. 206 . 0 . 0 . 391 . 334 266 . 210. 206 . 185. 229 . 363. 338 422. 400 . 420 . 314. 360 . 486 . 339 319. 275. 270 . 216 . 274. 416 . 346 383. 380 . 379. 299. 342. 473. 351 449. 440 . 445. 345 . 402. 515. 365 464. 447 . 443 . 354 . 409 . 526 . 367 416 . 334. 347 . 295. 367 . 436 . 377 452. 432. 422. 358. 421. 538. 378 418. 3 93. 375. 326 . 395 . 520 . 379 385. 354. 339 . 290 . 361. 439. 384 460 . 434. 454 . 368 . 417 . 558. 383 614 . 635. 724. 515. 579. 721. 390 596 . 624. 715. 502. 564 . 711. 391 454 . 442. 472. 368. 431. 570 . 401 468 . 453. 506 . 36 0 . 422. 578 . 402 325 . 281. 310 . 212. 283 . 470 . 410 364 . 336 . 373. 250 . 324. 499. 411 47 6 . 472. 520 . 371. 430 . 533. 409 482. 433. 556 . 367 . 443. 607 . 1001 561 . 572. 643. 462. 518. 656 . 55 Table 8 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 1002 568. 569. 609. 635. 502. 662. 1003 603 . 660 . 716. 501. 570 . 7 0 0 . 10 04 598 . 619. 711 . 506 . 562. 693 . 1005 509. 500 . 530 . 3 98 . 653. 586 . 1006 515. 512. 563. 603 . 668 . 598. 1007 587. 532. 631. 660 . 522 . 652 . 1008 573. 535. 586 . 630 . 505 . 635 . 1009 573. 585. 620 . 652. 513. 630 . 1010 555 . 557 . 586 . 661. 693. 621. 1011 515. 518. 560 . 618. 0 . 585. 1012 563. 572. 616 . 666 . 520 . 661. 1013 606 . 639. 766 . 692. 615. 755. 1016 583. 607 . 636. 662. 535. 656. 1016 582. 607 . 666 . 500 . 551. 689. 1018 600 .. 623 . 702. 506 . 566 . 7 06 . 1019 538 . 563 . 600 . 650 . 501 . 636 . 2002 611 . 395 . 612. 321. 376. 693. 2003 537 . 566. 611. 628 . 695 . 606. 2005 379. 353. 361. 260 . 330 . 660 . 2006 508. 506 . 516 . 392. 651 . 570 . 2007 500 . 697 . 509 . 605. 653. 565. 2008 616. 668. 716 . 522. 537 . 707 . 2009 521. 527 . 551. 630 . 683. 601 . 2010 520 . 526 . 57 9. 622. 68 0 . 621 . 2011 566 . 576 . 668. 676. 523 . 666 . 99991 556 . 577 . 653 . 665. 513. 660 . 99992 679 . 650 . 671 . 373. 630 . 579. 99993 630 . 676 . 525. 382. 630 . 583 . VI 676 . 763. 815. 555 . 658. 780 . V2 617 . 630 . 766 . ' 560 . 620 . 726 . V 3 561 . 603. 713. 0 . 0 . 700 . V6 566 . 621. 728. 666 . 558 . 716 . V6 552. 572. 632. 66 6. 520. 6 36 . V7 696 . 520 . 610. 0 . 0 . 582. V8 662. 712. 796 . 565. 661 . 777 . Al 631 . 682. 751. 511. 610 . 767 . A2 612. 635. 756 . 517 . 613. 750 . A 6 580 . 610. 700 . 686 . 553. 707 . A6 686 . 526. 593. 385. 675 . 613. A9 536 . 616. 700 . 500 . 565. 713. A18 666 . 725. 812. 563. 638. 802. A19 611. 6 57. 763. 507 . 581 . 722. R1 622. 658. 638. 556 . 606 . 626 . R2 655 . 6 7 0 . 729. 526 . 593 . 725 . R3 660 . 661. 69] . 523. 590 . 706 . R8 586 . 601. 6 5 7 . 6SS . 562. 679 . RIO 66 0 . 66 2. 717... 522. 590 . 715. Rll 615. 638. 696. 506 . 557 . 636 . R23 536 . 593 . 660. 635. 560 . 668. R26 566 . 580 . 671. 666 . 528. 665. Table 3 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS R26 614. 643. 711. 523. 580 . 715. R36 564. 583. 661. 475. 530 . 669 . R3S 500 . 491. 512. 397. 453 . 561 . R51 646 . 675 . 730 . 538. 604 . 725. R79 594. 621. 688. 502. 558. 697 . 2012 374. 331. 330 . 251. 325. 488. 57 Table 9: Cen, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Stars are identified on Figure 1 1 . STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS 001 9996 . 9996 . 9829. 9897 . 5192. C 002 9893 . 9798. 9693 . 9632. 9 99 9 . 0 . 003 5216 . 5121. 5005. 5058 . 5950 . 0 . 0 0 A 9788 . 9799. 9599 9599. 9832 . 0 . 005 9 936 . 9932. 9790 . 9799 . 517 9. 0 . 006 9997 . 9923. 9752. 9728 . 5079 . 0 . 007 9909 . 9896 . 9657. 9632 . 9915. 0 . 008 5069 . 9998. 9899. 9855 . 5239. 0 . 009 5058 . 9988. 9825. 9805 . 5165. 0 . 010 9979 . 9990 . 9736 . 9707 . 5099 . 0 . Oil 5038 . 9970 . 9875. 9856 . 5193. 0 . 012 9890 . 9780 . 9681. 9622 . 9995. 0 . 013 5059 . 9986 . 9819. 9790 . 5122. 0 . 013.5 5205 . 5001 . 9935. 9919. 5232. 0 . 019 5002. 9961 . 9767. 9728 . 5001 . 0 . 015 5173. 5090 . 9 9 31. 9901 . 5210 . 0 . 016 5027 . 9985. 9887. 9721. 5099 . 0 . 017 9355. 9812. 9596 . 9517 . 9825. 0 . 018 5029 . 9998. 9837 . 9755 . 5035 . 0 . 019 5029. 9962. 9782. 9717. 5026 . 0 . 020 5119. 5062. 9897 . 9891 . 5139. 0 . 021 5196 . 5089. 9929. 9868. 5219. 0 . 023 9969 . 9997 . 9703 . 9629. 9978 . 0 . 029 9899 . 9892. 9621. 9509 . 9868. 0 . 025 9987 . 9929. 9705 . 9653. 5053. 0 . 025.5 5017 . 9957. 9750 . 9700 . 5039 . 0 . 026 9966 . 9903. 9793. 9659 . 5001 . 0 . 027 9882. 9803. 9660 . 9558 . 9975. 0 . 028 9982. 9908. 9799. 9677 . 5080 . 0 . 029 9920 . 9929. 9706 . 9682 . 5192. 0 . 030 5167. 5052. 9992. 9929 . 5318 . 0 . 031 5031 . 9999. 9897. 9800 . 5193. 0 . 031.5 5202. 5059. 5001 . 9932. 5367 . 0 . 032 9889 . 9799 . 9632. 9581 . 9969. 0 . 033 5092. 9917. 9837. 9778 . 5156. 0 . 039 5025. 9893. 9820. 9755 . 5159. 0 . 035 9802. 9790 . 9621 . 9592. 9885. 0 . 036 5037 . 9928. 9876 . 9833 . 5189. 0 . 037 9709 . 9699. 9568. 9512. 9355 . 0 . 038 9829. 9776 . 9705. 0 . 5005 . 0 . 039 9795. 9732. 9618. 9536 . 9395. 0 . 090 9796 . 9669. 9586. 9503. 9659. 0. 091 9995 . 9869. 9820 . 9716 . 5095. 0 . 092 9725 . 9701 . 9607 . 9523 . 9369. 0 . 093 9710'. 9668. 9635. 9560 . 9859 . 0 . 099 9850 . 981 0 . 9699. 9552. 9990 . 0 . 095 5029. 9 97 5. 9892. 9897 . 5185. 0 . 096 5106 . 5 01 6 . 9939. 9927 . 5337 . 0 . 097 5112. 5010 . 5006. 9966 . 5312. 0 . 098 9992. 9929. 9879. 9827 . 5168. 0 . Table (continued) 1 IRIS A IRIS B IRIS C IRIS A IRIS IRIS STAR o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 049 4882. 4837 . 4799 . 4703 . 5042. 050 5123. 5003 . 5007 . 4946 . 5347 . 051 4818. 4776 . 4732. 4612. 4973 . 051.5 4970 . 4867 . 4843 . 4762. 5171. 052 4626 . 4592. 4565 . 4417 . 4772. 0525 5037 . 4940 . 4921. 4832. 5212. 053 4829 . 4763. 4730. 4616 . 4968. 054 4803 . 4774 . 4724 . 4632 . 4958 . 055 4728. 4710 . 4671 . 4556 . 4863. 05.5 4959 . 4891. 4903. 4790 . 5138, 056 4927 . 4868. 4850 . 4750 . 5122. 057 4795 . 4714. 4716 . 4606 . 4934 . 053 4834. 4817. 4714 . 4658. 5023 . 059 4838 . 4795. 4747 . 4664. 5013. 065.5 5034.- 4958. 486 0 . 4887 . 5234 . 061 4984 . 4734 . 4495. 4821. 4895. 062 4999 . 4923. 4805. 486 5 . 5180 . 063 4863 . 4833. 4923 . 4710 . 5056 . 064 4890 . 4837 . 4743. 4717. 5091 . 065 4699. 4727 . 4413. 4505. 4777 . 066 4943 . 4859. 4795. 4773 . 5149. 067 5035. 4955. 4900 . 4 913. 5258. 082.5 4944 . 4871 . 4872 . 4757 . 5116 . 069 5195. 4996 . 5055. 4874. 5383. 070 4682. 4587. 4471 . 4367 . 4786 . 071 4764 . 4676 . 4607 . 4507 . 4880 . 072 4838 . 4782. 4679. 4627 . 5005 . 073 4956 . 4877 . 4836 . 4791 . 5129. 074 5004. 4924. 4904. 4857 . 5201 . 075 4764 . 4675 . 4611. 4508. 4898 . 076 4784 . 4719. 4603 . 4589. 4901. 077 4733. 4725. 4671 . 4568. 4924 . 078 4737 . 4697 . 4678. 4558. 4867 . 079 4829. 4800 . 4768. 4649. 4999. 080 4909. 4848. 4873 4721 . 5087 . 081 4878. 4851. 4813 4709. 5044 . 082 4577 . 4570 . 44SS 4344 . 4717 . 083 4532. 4505. 4420 . 4328. 4649. 084 4807 . 4763 . 4741 . 4630 . 4966 . 085 4605. 4581 . 4446 . 4395. 4719. 085.5 4926 . 4842. 4846. 4737 . 5089 . 086 4957 . 4906 . 4859. 4800 . 5197. 086 .5 5043. 4931 . 4943. 4866 . 5216 . 087 4862. 4837 . 4770 . 4707 . 5075 . 0S8 4731 . 4708. 4614. 4528. 4378. 088.5 5096 . 5003 . 4998 . 4918. 5306 . 089 4686 . 4653. 4611. 4505. 4805. 090 4677 . 4643. 4607 . 4477 . 4794 . 091 4788. 4730 . 4753. 4587 . 4925. 091.5 4710. 4660 . 4640 . 4465. 4787 . 9 (continued) 1 STAR IRIS A IRIS B IRIS C IRIS A IRIS B 092 4703. 4661 . 4665 . 4520. 4836 . 0 092.5 4744 . 4707 . 4682. 4526 . 4856 . 0 0 94 4725. 4705. 4633. 4498. 4859 . 0 095 4844 . 4764. 4730 . 4587 . 4965. 0 095 .5 4927 . 4876. 4854 . 4679. 5160 . 0 096 4788. 4735. 4698 . 4547 . 4925. 0 097 4712. 4683. 4650 . 4483 . 4829. 0 098 4833. 4741 . 4774. 4599. 4954. 0 099 4914. 4837. 4839. 4661. 5034. 0 099 .5 4885. 4803. 4803. 4600 . 4972. 0 100 4826 . 473 0. 4747 . 4662. 4 989. 0 100.5 4982 . 4916. 4903. 4793. 5154. 0 101 4821 . 4784. 4750 . 46 36 . 4976 . 0 101.5 4946 . 4883. 487 3 . 4751 . 5101. 0 102 486 9.. 4824. 4741 . 4691 . 5037. 0 103 4994 . 4 948. 4 9 0 2 . 4818. 5187 . 0 103.5 4984 . 4931. 4908 . 4818. 5181. 0 104 4646 . 4644 . 4570 . 4454. 4746 . 0 105 4749 . 4726 . 4692 . 4536 . 4859. 0 105.5 4976 . 4902. 4920 . 4758 . 5114. 0 106 4626 . 4613. 4567 . 4438 . 4727 . 0 106 .5 4917 . 4841 . 4826 . 4712. 5054. 0 107 4660 . 4658. 4578. 4418. 4732. 0 108 4708 . 4707 . 4646 . 4489. 4843. 0 108.5 4373. 4837. 4806 . 4 6 4 3. 5000 . 0 109 4750 . 4735. 4673. 4495. 4329. 0 109.5 4699 . 4683. 4618. 4434. 4752 . 0 110 4944 . 4871 . 4866 . 4704 . 5057 . 0 111 4736 . 4700. 4683. 4526 . 4324 . 0 112 4818 . 4789. 4796 . 4568. 4918 . 0 113 4920 . 4899. 4366 . 4711. 5007 . 0 114 4804 . 4792. 4707 . 4554 . 4849. 0 116 4664 . 4634. 4594 . 4395. 4709 . 0 117 4890 . 4854. 4802. 4616 . 4977 . 0 118 4602. 4538. 4503. 4300 . 4631 . 0 119 4646. 4618. 4530. 4335. 4704. 0 120 4632 . 4567. 4513. 4290 . 4684. 0 122 4510 . 4505. 4382. 4179. 4525. 0 123 4621 . 4592. 4502. 4296 . 4642. 0 125.5 4933 . 4837. 4762. 4630 . 5016 . 0 126 4720 . 4667 . 4562. 4397 . 4734 . 0 126.5 4986 . 4891. 4814. 466S. 5074 . 0 127 4720 . 4654. 4630 . 4462. 4867. 0 127.5 4890 . 4826 . 4776 . 4669 . 5058. 0 128 4893 . 4790 . 4765. 4609. 4977 . 0 129 4565. 4500. 4435. 4283. 4 6 7 5. 0 130 4968 . 4866 . 48321 4726 . 5110 . 0 131 4 9 S 8 . 4891 . 4823. 4721 . 5150 . 0 132 4813. 4718. 4681. 4534 . 4928. 0 133 4763. 4684. 4616 . 4515. 4906 . 0 60 Table 9 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS 134 4637 . 4634. 4589 . 4461. 4732. 0. 136 4356 . 4790 . 4638 4533. 4899. 0 . 137 4G62. 4767 . 4703. 4540 . 4927 . 0 . 137 .5 4949 . 4893 . 4793 . 4660 . 5012. 0 . 133 4340 . 4816 . 4657 . 4558. 4855. 0 . 138.5 4356 . 4838. 4663. 4544 . 4922. 0 . 141 4969. 4959. 4330 . 4727 . 5013. 0 . 143 4988. 4814. 4615. 4785. 4860 . 0 . 61 i Table IQ: M5, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Arp (1955) except for 5001 to 99992 which are identified on Figure 12. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 1001 363 . 363. 381. 0 . 0 . 0 . 1002 398 . 415. 412. 0 . 0 . 0 . 1003 359 . 353. 372. 0 . 0 . 0 . 1004 457 . 476 . 446 . 0 . 0 . 0 . 1005 394. 386 . 390. 0 . 0 . 0 . 1003 336 . 307 . 357 . 0 . 0 . 0 . 1012 353. 36 0 . 359. 0 . 0 . 0 . 1014 505. 515. 433 . 0 . 0 . 0 . 1015 353. 359. 359. 0 . 0 . 0 . 1020 583. 574. 567 . 0 . 0 . 0 . 1021 393. 397 . 390 . 0 . 0 . 0 . 1025 431. 4 42. 421 . 0 . 0 . 0 . 1031 336 . 328. 343. 0 . 0. 0 . 1035 382 . 388. 372. 0 . 0 . 0 . 1036 330 . 329 . 348 . 0 . 0 . 0 . 1039 485'. 487 . 432. 0 . 0 . 0 . 1040 336 . 314. 344 . 0. 0 . 0 . 1043 336 . 337. 335. 0 . 0 . 0 . 104 9 326 . 323. 333 . 0 . 0 . 0 . 1050 404 . 401. 383 . 0 . 0 . 0 . 1055 4 03. 413. 400 . 0 . 0 . 0 . 1056 330 . 306 . 355. 0 . 0 . 0 . 1057 335. 326 . 339 . 0 . 0 . 0 . 1058 4 6 7. 430 . 443 . 0 . 0 . 0 . 1059 353 . 339. 349. 0 . 0 . 0 . 1061 454 . 46 3. 433. 0. 0. 0. 1067 373. 377 . 371. 0 . 0 . 0 . 1068 583. 585. 583. 0 . 0 . 0 . 1071 48 9. 493. 486 . 0 . 0 . 0 . 1074 386 . 388 . 534 . 0 . 0 . 0 . 1075 331 . 312. 337 . 0 . 0 . 0 . 1080 336 . 377. 390 . 0 . 0 . 0 . 1081 407 . 411. 403 . 0 . 0 . 0 . 2001 353. 351. 375. 0. 0 . 0 . 2007 318. 314. 359 . 0. 0 . 0 . 2009 593. 539. 562. 0 . 0 . 0 . 2012 330. 332. 36 3. 0 . 0 . 0 . 2018 365. 358. 373 . 0 . 0 . 0 . 2020 341. 323. 355. 0 . 0 . 0 . 2024 370 . 357 . 382 . 0 . 0 . 0 . 2031 338. 328. 350 . 0 . 0 . 0 . 2039 363. 363 . 376 . c . 0 . 0 . 2045 334. 320 . 360 . 0 . 0. 0 . 2050 40 3. 398. 393. 0 . 0 . 0 . 2051 37 9. 387 . 383 . 0 . 0 . 0. 2 0 54 371. 371. 378 . 0 . 0 . 0 . 2059 470 . 484 . 453 . 0 . 0. 0. 2061 435. 427 . 4 28 . 0 . 0 . 0 . 2063 322. 308 . 351. 0 . 0 . 0 . 2069 367 . 367 . 376 . 0 . 0 . 0 . Table 10 (continued) STAR IRIS A IRIS :ris c IRIS A IRIS IRIS 207 A 414 . 420 . 396 . 0 . 0 . 2080 372. 333. 358. 0 . 0 . 2085 619. 614. 590 . 0 . 0 . 2086 449. 458. 427 . 0 . 0 . 2093 364 . 363 . 359. 0 . 0 . 3003 615. 609 . 522 . 0 . 0 . 3006 334 . 327 . 327 . 0 . 0 . 3007 336 . 318. 335. 0 . 0 . 3009 340 . 330 . 318. 0 . 0 . 3012 355. 358. 340 . 0 . 0 . 3013 334 . 331. 336 . 0 . 0. 3015 375. 377 . 343. 0 . 0 . 3016 369. 380 . 336 . 0 . 0 . 3018 463. 471. 394 . 0 . 0 . 3019 37 3.- 378. 341. 0 . 0 . 3024 418. 422. 342. 0 . 0 . 3026 374. 372 . 351 . 0 . 0 . 3030 335. 319 . 342. 0 . 0 . 3031 367 . 363 . 355 . 0 . 0 . 3032 373. 381. 360 . 0 . 0 . 3036 538. 542. 485. 0 . 0. 3048 351. 350 . 34 0. 0. 0 . 3049 338. 321. 333 . 0 . 0 . 3050 515. 527 . 458. 0 . 0 . 3052 384. 385. 360 . 0 . 0 . 3053 417. 433. 381 . 0 . 0 . 3056 441 . 459. 410 0 . .0 . 3059 388. 401. 377 . 0 . 0. 3062 357 . 356 . 363. 0 . 0 . 3066 376 . 385. 372. 0 . 0 . 3067 444 . 452. 417 . 0 . 0 . 3078 546 . 551. 563. 0 . 0 . 4003 326. 313. 356 . 0 . 0 . 4004 364. 370 . 386 . 0 . 0 . 4006 344. 340 . 378. 0. 0 . 4010 34 9. 345 . 379. 0 . 0 . 4011 368. 374. 404. 0. 0 . 4012 413. 424. 456 . 0. 0 . 4019 531. 541. 574. 0 . 0 . 4022 315. 308 . 357 . 0 . 0 . 4026 375. 388. 431 . 0. 0 . 4028 335. 331 . 379. 0 . 0 . 4030 403. 419. 435. 0 . 0 . 4033 347 . 344 . 383. 0 . 0 . 4 0 34 456 . 469 . 521 . 0 . 0. 4035 322. 305. 361. 0 . 0 . 4036 366 . 367 . 4 0'5 . 0 . . 0. 4 0 37 331 . 325. 368. 0 . 0 . 4040 321. 320 . 358. 0 . 0 . 4047 588. 595. 616. 0 . 0 . oooooooooooooooooooooooooooooooooooooooooooooooooo 63 Table 10 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C CDOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 4049 470 . 484. 494. 0 . 0 . 4056 470 . 486 . 485. 0. 0. 4059 530 . 53 9 . 557. 0. 0. 4065 350 . 347 . 373. 0. 0. 4067 323. 319. 359. 0. 0. 4072 489. 502. 539. 0. 0. 4073 357 . 361 . 398. 0. 0. 4074 409 . 422. 451. 0. 0. 4078 354. 355 . 403. 0. 0. 4 081 593. 599. 665. 0. 0. 4082 423. 445. 497. 0. 0. 5001 688. 681. 671. 0. 0. 5002 467 . 484. 450. 0. 0. 5003 454. 469 . 432. 0. 0. 5004 391. 409. 387. 0. 0. 5005 '419. 442. 416 . 0 . 0. 5006 332. 320 . 345. 0. 0. 5007 412. 435. 412. 0. 0. 5003 586 . 591. 579. 0. 0. 5009 526. 540 . 521. 0. 0. 5010 370 . 373 . 382. 0. 0. 5011 380 . 401. 407 . 0 . 0 . 5012 420 . 442. 436. 0. 0. 5013 357 . 366 . 384. 0. 0. 5014 342. 338 . 359. 0. 0. 5015 359. 376 . 385. 0. 0. 5016 483. 501. 462. 0. 0. 5017 458. 478. 430. 0. 0. 5018 629. 636 . 584. 0. 0. 5019 553. 561. 500. 0. 0. 5020 36 9. 371. 555 . 0. 0 . 5021 598. 599. 531. 0. 0. 5022 674 . 661. 611. 0. 0. 5023 510. 532. 473. 0. 0. 5024 388. 403 . 371. 0. 0. 5025 335. 329. 0 . 0 . 0 . 99991 560 . 422. 515. 0. 0. 99992 390 . 377 . 381. 0. 0. 64 Table 11: M10, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Arp (1955) and Harris, Racine and De Roux (1975). STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 1002 778 . 706 . 726 . 0 . 0 . 0 . 1004 363. 350 . 334. 0 . 0 . 0 . 1009 432 . 447 . 453. 0 . 0 . 0 . 1013 369 . 360 . 387 . 0 . 0 . 0 . 1015 546 . 570. 577 . 0 . 0 . 0 . 1013 458. 488. 509 . 0 . 0 . 0 . 1023 341 . 330 . 373 . 0 . 0 . 0 . 1024 453. 480 . 503 . 0 . 0 . 0 . 1025 519 . 530 . 550 . 0 . 0 . 0 . 1023 372 . 367. 4 02. 0 . 0 . 0 . 1035 469 . 490 . 499. 0 . 0 . 0 . 1039 365 . 385. 412. 0 . 0 . 0 . 1042 452. 475. 505. 0 . 0. 0 . 1043 338. 315. 374. 0 . 0 . 0. 1044 335.- 297 . 373. 0 . 0 . 0 . 104S 392. 414. 453 . 0 . 0 . 0 . 1049 367 . 330 . 416 . 0 . 0 . 0 . 1054 324. 295. 360 . 0 . 0 . 0 . 1055 337. 327. 379. 0 . 0 . 0 . 1056 439. 458 . 497 . 0 . 0 . 0. 1057 333. 314. 373. 0 . 0 . 0 . 1060 497 . 526 . 556. 0 . 0 . 0 . 1061 519. 527 . 545. 0 . 0 . 0 . 1063 399. 412. 429 . 0 . 0. 0 . 1069 335. 303. 378. 0 . 0 . 0. 1070 358 . 408. 466 . 0 . 0 . 0 . 1076 329. 300 . 382. 0 . 0 . 0 . 1078 349. 328. 395. 0 . 0. 0 . 2002 424. 430 . 437 . 0 . 0 . 0 . 2007 353. 329. 363. 0 . 0 . 0 . 2011 387 . 400 . 402. 0 . 0. 0 . 2015 410 . 413. 416 , 0 . 0 . 0 . 2024 766 . 699 . 688. 0 . 0 . 0 . 2032 392. 384. 392 . 0 . 0 . 0 . 2036 509 . 512. 503. 0 . 0 . 0. 2037 455. 457. 456 . 0 . 0 . 0 . 2043 340 . 335. 374. 0. 0 . 0 . 2046 353. 321. 365 . 0 . 0 . 0 . 2049 386 . 398. 421. 0 . 0 . 0 . 2050 653. 616. 633 . 0 . 0 . 0 . 2052 394 . 402. 420 . 0 . 0 . 0 . 2053 332. 300 . 351. 0 . 0 . 0 . 2057 379. 381. 397 . 0 . 0 . 0 . 2060 358. 342. 354 . 0 . 0 . 0 . 2065 353. 334. 371. 0 . 0 . 0 . 2067 370 . 370 . 398. 0 . 0 . 0 . 2063 395. 403. 417 . 0 . 0 . 0 . 2071 327 . 300 . 356 . 0. 0 . 0 . 2072 643. 614. 606 . 0 . 0 . 0 . 2074 403. 414. 415 . 0 . 0 . 0. Table 11 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 2076 498. 495. 498. 0. 0. 2079 337 . 319. 351. 0. 0. 2082 332. 2S7 . 334. 0 . 0 . 20S3 356 . 323. 355. 0. 0. 2085 391 . 386 . 3 97. 0. 0. 2086 339. 326 . 357. 0. 0. 2037 360 . 344 . 363. 0. 0. 20 91 331. 284. 336. 0. 0. 2094 352. 352. 375. 0. 0. 2095 357 . 339. 366. 0. 0. 2098 418. 427 . 4 22. 0. 0. 2101 0. 315. 349. 0. 0. 2103 343. 310. 345. 0. 0. 2104 493. 491. 471. 0. 0. 2105 5 9 9.- 565 . 546. 0. 0. 3002 487 . 502. 466. 0. 0. 3004 361. 348. 361. 0. 0. 3005 603 . 587 . 571. 0. 0. 3006 36 9 . 351. 367. 0. 0. 3003 356 . 325. 352. 0. 0. 3016 6S9. 646 . 6 38. 0. 0 . 3019 359. 341. 358. 0. 0. 3021 757 . 687 . 634. 0. 0. 3022 357 . 349. 343. 0. 0. 3023 355. 337 . 349. 0. 0. 3026 366 . 340 . 346. 0. 0. 3027 345 . 328. 341. 0. 0. 3028 506 . 495. 416. 0. 0. 3029 539. 537 . 514. 0. 0. 3033 366 . 354 . 362. 0. 0. 3034 412. 427 . 404. 0. 0. 3038 357. 340 . 354: 0. 0. 3040 353. 337 . 348. 0. 0. 3046 362. 359. 348. 0. 0. 3047 382. 385. 368. 0. 0. 3053 457 . 452. 403. 0. 0. 3054 502. 501. 439. 0. 0. 3055 568. 552. 495. 0. 0. 3056 436 . 444. 401. 0. 0. 3059 367 . 378. 366. 0. 0. 3077 354. 348. 329. 0. 0. 3080 333. 307 . 311. 0. 0. 3031 433. 448. 587. 0. 0. 3083 348. 328. 320. 0. 0. 3085 558. 554. 439. 0. 0. 3083 335. 325. 341. 0. 0. 3090 338. 322. 323. 0. 0. 3091 484. 496 . 451. 0. 0. 3092 364 . 369. 348. 0. 0. 3093 544. 539. 500. 0. 0. 66 Table 11 (continued) IRIS IRIS C STAR IRIS A IRIS B IRIS C OOOOOOOOOOOOOOOOOOOOOOOOOOOOCDOOOOOOOOOOOOOOOOOOOOO 3095 330. 311. 326 . 0. 3099 357. 363. 390 . 0 . 9 0 01 393. 327. 399 . 0 . 9009 382. 911. 916 . 0 . 9005 395. 332. 369 . 0 . 9006 368. 366 . 382. 0 . 9008 975 . 999. 989 . 0 . 9019 337 . 319. 359. 0 . 9015 626 . 608 . 619. 0 . 9017 921. 99 0 . 959 . 0 . 9019 908 . 929. 935. 0 . 9020 903. 915. 918. 0 . 9023 927 . 956 . 995. 0 . 9025 367 . 379 . 381. 0 . 9029 396 .. 350. 359. 0 . 9030 59 9. 591. 531 . 0 . 9036 325. 312. 320 . 0 . 9090 306 . 281. 311. 0 . 9099 685. 632. 623. 0 . 9095 399. 359. 363 . 0. 9099 390 . 338. 363 . 0 . 9050 335 . 327 . 399 . 0 . 9053 390 . 329. 370 . 0 . 9059 939. 967 . 962. 0 . 9059 935. 959. 97 5. 0 . 9061 319. 308 . 337 . 0 . 9069 379. 398. 0 . 0 . 9067 392. 398. 370 . 0 . 9068 339. 390 . 369. 0 . 9079 350 . 361. 393 . 0 . 9082 339. 339. 369. 0 . 9035 902. 923 . 968 . 0 . 9086 989. 505 . 59 0 . 0 . 9087 360 . 377 . 929. 0 . 20001 397 . 329. 388. 0 . 20002 329. 293. 365. 0. 20099 799. 686. 701 . 0 . 20053 352. 332. 382. 0 . 20059 372. 357 . 379. 0 . 20060 393. 399. 910 . 0 . 20079 366 . 395. 397 . 0 . 20103 391. 392. 360 . 0 . 20106 355. 393. 330 . 0 . 20115 352. 329. 320 . 0 . 20135 395. 322. 318. 0 . 20139 391. 398 . 351. 0 . 20159 350. 358. 399. 0 . 20161 523. 533. 505. 0 . 20163 319. 289. 310 . 0 . 20217 590 . 597 . 600 . 0 . Table 11 (continued) ' IRIS IRIS STAR IRIS A IRIS B IRIS C o o o o 20218 430 . 446 . 503. 0 . 20224 372. 367 . 433. 0 . 20249 331 . 314. 393. 0 . 20000 632. 590 . 547. 0 . 68 Table 12: M12, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Racine (1975) except for 21901, 21902, 31901, 41901, 41902, and 90001 to 90018 which are all identified on Figure 14. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 11001 619. 622. 575. 0 . 0 . 0 . 11002 747 . 747 . 750 . 0 . 0 . 0 . 11016 570 . 577. 495. 0 . 0 . 0 . 11017 470 . 452. 390 . 0 . 0 . 0 . 11045 419. 401. 367 . 0 . 0 . 0 . 11048 480 . 486. 412. 0 . 0 . 0 . 11051 390 . 350. 347. 0 . 0 . 0 . 11056 439 . 412. 394 . 0 . 0 . 0 . 11065 380 . 345. 346 . 0 . 0 . 0 . 11067 420 . 407. 378 . 0 . 0 . 0 . 12005 390 . 365. 368. 0. 0 . 0 . 12025 570 . 582. 471. 0 . 0 . 0 . 12042 508. 523. 417. 0 . 0 . 0 . 12046 408 . 389. 344 . 0 . 0 . 0 . 12049 418.. 410 . 346 . 0 . 0 . 0 . 12058 388. 364. 346 . 0 . 0 . 0. 12065 536 . 560 . 451. 0 . 0 . 0 . 12062 351 . 637 . 325. 0 . 0 . 0 . 12070 533 . 551. 446 . 0 . 0 . 0 . 12086 470 . 487 . 417 . 0 . 0 . 0 . 12091 423 . 437. 377 . 0 . 0 . 0 . 12096 351 . 347 . 330 . 0. 0 . 0 . 21004 401 . 373 . 399. 0 . 0 . 0 . 21007 622 . 632. 641. 0 . 0 . 0 . 21010 400 . 334. 391. 0 . 0 . 0 . 21016 560 . 582. 595. 0 . 0 . 0 . 21028 361 . 338. 371 . 0 . 0 . 0 . 21030 369 . 345. 373. 0 . 0 . 0 . 21033 382. 378. 387. 0 . 0 . 0 . 21036 374 . 354 . 376 . " 0 . 0 . 0 . 21038 533 . 546 . 505. 0 . 0 . 0 . 21041 364 . 337. 362. 0 . 0 . 0 . 21044 353 . 336 . 361 . 0 . 0. 0 . 21048 350 . 334. 356 . 0 . 0 . 0 . 21054 851 . 836 . 54 0 . 0 . 0 . 0 . 21055 446 . 429. 410 . 0 . 0. 0 . 21057 381 . 362. 358. 0 . 0. 0 . 21063 511 . 525. 482. 0 . 0. 0 . 21067 360 . 357. 355. 0 . 0. 0 . 22004 354 . 339. 392. 0 . 0 . 0 . 22014 442. 445 . 473. 0 . 0 . 0 . 22032 341 . 353. 375. 0 . 0. 0 . 22 0 47 524 . 565. 560 . 0 . 0 . 0 . 22051 509. 539. 516 . 0 . 0. 0 . 22054 330 . 333. 349. 0. 0 . 0 . 22055 351. 354. 360. 0. 0. 0. 22063 519. 525. 456. 0 . 0 . 0 . 22065 377. 375. 356 . 0 . 0 . 0 . 22072 342. 322. 333. 0 . 0. 0 . 22073 353. 346. 343. 0. 0 . 0 . Table 12 (continued) STAR IRIS A IRIS B IRIS IRIS A IRIS B IRIS C 31003 468. 456 . 453 0 . 0 . 0 . 31006 443. 441. 421 0 . 0 . 0. 31007 390 . 356 . 380 0 . 0 . 0 . 31009 486 . 494 . 465 0 . 0 . 0 . 31013 476 . 462. 459 0 . 0 . 0 . 31021 468. 475. 470 0 . 0 . 0 . 31023 382. 358. 390 0 . 0 . 0 . 31026 459. 446. 449 0 . 0 . 0 . 31028 479 . 472. 495 0. 0 . 0 . 31033 394 . ■ 384. 406 0 . 0 . 0 . 31037 445. 435. 433 0 . 0 . 0 . 31052 374. 350 . 594 0 . 0 . 0 . 32022 370 . 345. 397 0 . 0. 0 . 32023 410 . 410. 439 0 . 0. 0 . 32025 405 - 389. 422 0 . 0. 0 . 32037 393 . 369. 421 0 .' 0 . 0 . 32039 416. 403. 441 0. 0. 0 . 32056 404 . 387 . 426 0. 0 . 0 . 41009 486 . 484. 4 38 0 . 0 . 0 . 41018 565. 574. 508 0 . 0 . 0 . 41020 650 . 659 . 598 0 . 0 . 0 . 41024 685. 696. 676 0 . 0 . 0 . 41031 496 . 500 . 4 56 0 . 0 . 0 . 41035 417 . 375. 379 0 . 0 . 0 . 41042 440 . 409. 382 0 . 0 . 0 . 41055 407 . 393. 380 0 . 0 . 0 . 41070 409 . 370 . 387 0 . 0 . 0 . 41076 642. 643. 619 0 . 0 . 0 . 41078 468. 480 . 450 0 . 0 . 0 . 42009 396 . 374. 387 0 . 0 . 0 . 42039 433. 428. 427 0 . 0 . 0 . 42063 512. 536 . 475 0. 0 . 0 . 42037 390 . 376. 382 0. 0. 0 . 42010 711. 713. 738 0 . 0 . 0 . 12901 404. 405. 369 0 . 0 . 0 . 12903 390 . 364. 345 0 . 0. 0 . 21901 741. 739. 737 0 . 0. 0 . 21902 564. 580. 574 0 . 0. 0 . 31901 405. 376 . 402 0 . 0 . 0 . 41901 597 . 603. 577 0 . 0 . 0 . 41902 783. 789. 90 0 . 0 . 0 . 90001 740 . 750 . 779 0 . 0 . 0 . 90002 610 . 623. 618 0 . 0 . 0 . 90003 648. 658. 619 0 . 0. 0 . 90004 639 . 647 . 618 0 . 0 . 0 . 90005 554. 557. 496 0 . 0 . 0 . 90006 610 . 618. 594 0 . 0. 0 . 90007 642. 649 . 637 0 . 0 . 0 . 90008 605. 616. 548 0. 0 . 0 . 90009 700 . 708. 695 0. 0. 0 . Table 12 (continued) STAR IRIS A IRI ■ > B c IRIS A IRIS 90010 536 . 542. 443. 0 . 0 . 90012 603 . 621. 573. 0 . 0. 90013 510. 506 . 462. 0. 0 . 90 0 1A 48 6 . 487 . 452. 0. 0 . 90015 ASS. 558 . 515. 0 . 0. 90016 509 . 501. 462. 0 . 0 . 90017 485. 478. 449. 0 . 0 . 90018 515. 503. 471. 0 . 0 . 71 Table 13: M92, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Sandage and Walker (1966) except for 13001 to 13015 which are identified on Figure 15. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 1013 320 . 324. 370 . 0 . 0 . 0 . 1014 330 . 328. 386 . 0 . 0 . 0. 1040 330 . 334. 365. 0 . 0 . 0 . 1067 469 . 474. 469. 0 . 0 . 0 . 1068 322 . 326 . 362. 0 . 0 . 0 . 2012 337 . 327. 385. 0 . 0 . 0. . 2024 343 . 344. 334 . 0 . 0 . 0. 2028 303. 305. 357 . 0 . 0 . 0 . 2039 363. 372. 404 . 0 . 0 . 0 . 02053 609 . 596 . 599 . 0 . 0 . 0 . 02070 515 . 508. 505. 0 . 0 . 0 . 02089 383 . 391. 401. 0 . 0 . 0 . 02120 342. 348. 371. 0 . 0 . 0 . 02121 405. 414. 416. 0 . 0 . 0. 03011 308.. 309. 362. 0 . 0. 0 . 03013 656 . 642. 700 . 0 . 0 . 0. 03065 606 . 597 . 614. 0 . 0. 0. 03081 353 . 357 . 378. 0 . 0. 0 . 03082 493 . 434. 472. 0 . 0. 0 . 03088 334 . 331. 368. 0 . 0 . 0. 03096 329 . 316 . 356 . 0 . 0 . 0 . 03098 347 . 349. 370 . 0 . 0 . 0 . 03109 326 . 322. 363. 0 . 0 . 0 . 04002 440 . 430 . 465. 0 . 0 . 0 . 04010 460 . 453. 465. 0 . 0. 0 . 04040 405. 400 . 404 . 0 . 0 . 0 . 04079 466 . 468. 4 44 . 0 . 0 . 0 . 04087 320 . 313. 352. 0 . 0. 0 . 04094 517 . 514. 500 . 0 . 0 . 0 . 05045 557 . 543. 525. 0 . 0 . 0 . 05069 348. 342. 363. 0 . 0 . 0. 05078 354 . 348. 364 . 0 . 0 . 0 . 05106 615. 593. 565. 0 . 0 . 0 . 06018 425. 422. 395. 0 . 0. 0 . 07010 437 . 425. 392. 0 . 0. 0 . 07018 662. 636 . 539. 0. 0. 0 . 07039 362. 355. 359. 0 . 0 . 0 . 07067 342. 344. 337 . 0 . 0. 0 . 07068 377 . 377 . 364. 0 . 0. 0 . 07079 380 . 389. 360 . 0 . 0 . 0 . 07080 415. 409. 369 . 0 . 0 . 0 . 07122 628 . 607 . 555. 0 . 0. 0. 08024 398. 385. 354. 0 . 0 . 0 . 08012 341. 333. 329. 0 . 0. 0 . 08043 341. 339. 337 . 0 . 0. 0 . 08044 388. 389. 353. 0 . 0. 0 . 09012 339. 327. 319. 0. 0. 0 . 09013 387 . 393. 345. 0 . 0 . 0 . 09030 355 . 354 . 329. 0 . 0. 0. 09049 407. 403. 350 . 0. 0 . 0 . Table 13 (continued) STAR IRIS A IRIS IRIS IRIS A IRIS B IRIS C 09077 366 . 362. 346 0 . 0 . 0 . 09039 370 . 371. 350 0 . 0 . 0 . 10049 607 . 595. 559 0 . 0 . 0 . 10065 345. 343. 340 0 . 0 . 0 . 10028 322. 325. 321 0 . 0 . 0 . 11014 369. 377 . 355 0 . 0 . 0 . 11019 498. 490 . 413 0 . 0 . 0 . 11027 323. 333. 345 0 . 0 . 0 . 11033 323. 330 . 333 0 . 0 . 0 . 12007 310. 316 . 339 0 . 0 . 0 . 12003 497 . 489. 462 0 . 0 . 0 . 12018 327. 337 . 350 0 . 0 . 0 . 12031 385. 383. 392 0 . 0 . 0 . 12034 445. 448 . 429 0 . 0 . 0 . 12045 371. 383. 379 0 . 0 . 0 . 13001 336 . 33S . 361 0 . 0 . 0 . 13002 376 . 378. 385 0 . 0 . 0 . 130 0 3 625. 60S. 598 0 . 0 . 0 . 13004 491. 490 . 434 0 . 0 . 0 . 13005 502. 498. 447 0 . 0 . 0 . 13006 595. 587 . 536 0 . 0 . 0 . 13007 638. 614. 561 0 . 0 . 0 . 13003 606 . 592. 526 0 . 0 . . 0 . 13009 620 . 612. 533 0 . 0 . 0 . 13010 662. 646 . 601 0 . 0 . 0 . 13011 648. 633. 599 0 . 0 . 0 . 13012 565. 557 . 519 0 . 0 •• 0 . 13013 398. 402. 400 0 . 0 . 0 . 13014 403 . 416 . 393 0 . 0 . 0 . 13015 387. 397 . 375 0 . 0 . 0 . 73 Table 14: NGC 6397, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Woolley et al. (1961) except for 901 to 903 which are identified on Figure 16. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 043 565 . 568. 570 . 487 . 453. 572. 047 364. 290 . 397 . 304 . 251. 380 . 082 349 . 270 . 318. 280 . 223. 310 . 083 400 . 373. 417 . 326 . 26 9. 399 . 085 395. 348 . 403. 318. 275 . 372. 089 370 . 338. 393. 306 . 265. 354 . 099 619. 619. 601. 522. 492 . 599 . 128 410 . 444 . 450 . 350 . 305. 410 . 132 335. 383. 385. 303 . 259 . 336 . 139 280 . 313. 307 . 243. 204. 271 . 140 372. 402. 391. 305. 274. 333. 143 288. 312. 315. 230 . 194. 267. 144 500 . 503. 493. 424 . 332. 470 . 158 497 . 516 . 496 . 416 . 387 . 463. 179 537 , 554 . 5 34. 456 . 418 . 491 . 164 347 . 377 . 384. 300 . 225. 325. 194 373. 374. 365. 304 . 258 . 335. 198 384. 429. 408. 323. 290 . 362. 199 388 . 425. 414. 336 . 294. 363. 205 360 . 0 . 360 . 296 . 242. 333. 208 515. 521. 492. 422 . 3S0 . 485 . 235 488. 498 . 447 . 387 . 355. 460 . 251 568. 570 . 530 . 462. 426 . 541. 265 367 . 408 . 385. 303 . 261. 334. 278 415. 450 . 417 . 355. 304. 380 . 281 540. 555. 525. 432. 400 . 47 3. 283 600 . 623. 570 . 487 . 444 . 535. 285 380 . 410. 395. 324. 271. 346 . 288 296 . 334 . 336 . 261. 203 . 276 . 291 660 . 670 . 625. 537 . 507 . 605 . 296 550 . 57 4 . 541. 450 . 427 . 493 . 318 632. 639. 600 . 520 . 436 . 571 . 323 369. 405 . 389. 297 . 251 . 327 . 330 375. 411. 389. 305. 259. 331. 347 418. 441. 0 . 34 3 . 0 . 364. 353 448. 471. 435. 374. 320 . 403 . 354 480 . 501. 460 . 389. 333. 4 33. 357 345. 369 . 366 . 284. 252. 308. 359 480 . 506 . 465 . 398 . 354. 429. 364 287. 3C4. 312. 236. 193 . 253. 368 360 . 381. 375. 300 . 252. 520 . 375 574 . 5 9 0. 544. 473. 439 . 503. 376 427 . 450 . 436 . 360 . 315. 387. 386 455 . 47 0 . 446 . 371. 329. 394. 387 617 . 621. 582. 494. 474 . 550 . 392 355 . 384. 376 . 302. 24 0 . 320 . 393 329. 356 . 340 . 273. 224. 295. 3 94 375 . 393. 380 . 305 . 265. 341. 397 461. 473. 454. 388. 351. 422. 404 470 . 492. 472. 393. 358. 434. 74 Table 14 (c o n tin u e d ) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C AOS 395 . A20 . 410. 330 . 289. 363. All A98 . 507 . 491. 410 . 374. 445 . A17 392. A 0 5. 403. 328 . 292. 356 . A20 395 . A15. 404 . 337 . 296 . 373 . A22 A 0 9 . AA6 . 480 . 360 . 333. 443. A25 683 . 683. 670 . 583. 543. 700 . A28 520 . 536 . 530 . 444. 409 . 523. A3A 3A5. 403. 403. 308. 259. 368. A59 555. 558. 570 . 476 . 441 . 531 . A68 522. 537 . 531. 452. 418. 518. A69 700 . 706 . 704. 6 03 . 575. 720 . A73 A50 . A7 0 . 455. 390 . 348. 417 . A7 6 A88. 501. 483. 420 . 335. 442. A79 A65. 474. 445. 390 . 344. 410 . A8A 335.. 351. 320 . 290 . 242. 270 . 501 A61. 470 . 443 . 380 . 337 . 403 . 503 368. 370 . 353. 304 . 252. 301. 511 503. 518. 483. 421. 388. 461 . 519 33A . 332. 312. 272. 214. 285. 521 260 . 259. 227 . 216. 154. 206 . 555 382. 391. 365. 314. 267. 327 . 56 A AO5 . 416. 380 . 333. 292. 349 . 565 A31. 438. 421. 362. 314. 393 . 566 A63. 504. 460 . 413. 372 . 436 . 57 A 381. 396 . 358 . 317. 271. 322. 575 A30 . 457. 423. 371. 325. 387 . 603 660 . 669. 624. 560 . 529. 641. 605 380 . 391. 358. 327 . 272. 332 901 500 . 514. 484. 408. 380 . 446 . 902 534 . 597 . 547 . 476 . 443. 4 93 . 903 650 . 658. 619. 550 . 514. 620 . 75 Table 15: NGC 6752, Uncorrected Iris Readings. Uncorrected iris readings are given for each plate in each filter. Star numbers are from Alciano (1972) except for 901 to 911 which are identified on Figure 17. STAR IRIS A IRIS B IRIS C IRIS A IRI5 B IRIS C 001 339. 432. 467 . 0 . 0 . 467 . 002 363 . 407. 431. 0 . 0 . 385. 003 436 . 478. 512. 0 . 0 . 498. 003 418. 463 . 487 . 0 . 0 . 463 . 009 489 . 524. 562. 0 . 0 . 555. 010 302. 356 . 360 . 0 . 0 . 307 . 011 342. 332. 390 . 0 . 0 . 345. 012 495. 524. 566 . 0 . 0 . 556 . 016 523 . 568. 633 . 0 . 0 . 630 . 018 508 . 531. 532. 0 . 0 . 573. 019 271 . 309 . 335. 0 . 0 . 285. 029 415 . 443. 485. 0 . 0 . 458 . 030 361. 388. 425. 0 . 0 . 390 . 031 536 . 568. 640 . 0 . 0 . 623. 033 403 , 261. 450 . 0 . 0 . 230 . 0 3 A 327 . 373 . 400 . ' 0 . 0 . 332. 035 365 . 425. 467 . 0 . 0 . 426 . 036 452 . 484. 536 . 0 . 0 . 517 . 042 463 . 497 . 551. 0 . 0 . 544 . 0 A 3 377 . 416 . 463 . 0 . 0 . 447 . 044 477 . 520 . 570. 0 . 0 . 570 . 045 477 . 517 . 570 . 0 . 0 . 571. 046 295 . 351. 410 . 0 . 0 . 367 . 0 48 238 . 335. 393 . 0 . 0 . 564 . 055 383 . 430 . 487 . 0 . 0 . 468 . 058 335. 380 . 424. 0 . 0 . 376 . 059 555. 601. 664 . 0 . 0 . 663 . 060 352 . 404. 446 . 0 . 0 . 409 . 061 483. 520 . 563 . 0 . 0 . 554 . 063 314. 385. 418. 0 . 0 . 382 . 068 430 . 447 . 520 . 0 . 0 . 501. 069 294 . 355. 360 . 0 . 0 . 300 . 070 351 . 405. 476 . 0 . 0 . 430 . 077 337 . 380 . 423. 0 . 0 . 374. 083 552. 595. 642. 0 . 0 . 647 . 092 323 . 372. 400 . 0 . 0 . 336 . 104 330 . 384. 401. 0 . 0 . 353. 105 409. 45 9. 491. 0 . 0 . 458. 113 391 . 438 . 462. 0 . 0 . 431. 140 323 . 374. 401. 0 . 0 . 352. 159 263 . 326 . 360 . 0 . 0 . 302 . 180 411 . 466 . 497 . 0 . 0 . 478 . 210 330 . 3 92. 436 . 0 . 0 . 389. 212 454 . 492. 540 . 0 . 0 . 0 . 238 486 . 524. 571. 0 . 0 . 565. 251 519 . 556 . 610 . 0 . 0 . 610 . 275 515 . 551. 605. 0 . 0 . 595 . 276 450 . 490 . 537 . 0 . 0 . 520 . 281 369 . 415. 46 0 . 0 . 0 . 428 . 284 497 . 520 . 579. 0 . 0 . 573. 76 Table 15 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 301 345. 395 . 432. 0 . 0 . 339. 302 300 . 354 . 383. 0 . 0 . 330 . 308 315. 374. 413. 0 . 0 . 363. 319 346 . 391. 427 . 0 . 0 . 378 . 323 493. 338 . 577 . 0. 0 . 565. 32 A 374 . 418. 452. 0 . 0 . 420 . 327 263. 329. 363. 0 . 0 . 293. 336 369. 430 . 456 . 0 . 0 . 422. 901 379. 426 . 459 . 0 . 0 . 423. 902 554. 601. 645 . 0 . 0 . 633. 903 356 . 405. 446 . 0 . 0 . 406 . 904 268. 332. 374. 0. 0. 320 . 905 508. 550 . 560 . 0 . 0 . 550 . 906 402. 455. 489. 0 . 0 . 461. 907 341 . 393 . 437 . 0 . 0 . 391. 908 459. 511. 545. 0. 0 . 526 . 909 460 . 508 . 536 . 0 . 0 . 521. 910 456 . 495. 550 . 0 . 0 . 550 . 911 578. 624. 675. 0 . 0. 636. 77 Figure 18. Density map of flat illumination plate. Iso-sensitivity zones are labeled 1 to 6 . 78 This problem is normally solved by obtaining photoelectric photometry for a large number of stars on the plate and mapping corrections to the iris photometry as a function of plate position. This approach cannot reasonably be applied to the survey-systern photographic photometry since one purpose of the survey technique is to reduce the amount of photoelectric observing required. The approach I have used involves the derivation of pseudo-photoelectric photometry in the survey system from B, V photometry which is available for most of the globular clu ste rs. The pseudo-survey-system photometry is used to remove the sensitivity variation from the iris photometry for each cluster. The procedure for each plate of each cluster is the followi ng: 1) Flat field illum ination plates are used to divide the plate into iso-sensitivity zones. 2) Pseudo-magnitudes in filters A, B and C are calculated from the B, V or V, I photometry, whichever is available, for stars in each cluster. The calculation is based on the mean relationships for survey-system standard stars between V-m^, V-mg, V-m^ and B-V color or I-m^, I-m^, I-m^ and V-I color. 3) A quadratic curve is fit by least squares to the relation between the pseudo-magnitude and ir is measurements for stars in each iso-sensitivity zone on a plate. 4) The difference between iso-sensitivity zones is assumed to be a simple offset equal to the differences among the constant coefficents in the quadratics for each iso-sensitivity zone. Corrected iris readings are produced for each plate by applying these differences. 79 Two implicit assumptions remain: first, that only the constant coeffi cents in the quadratics are different in different iso -se n sitiv ity zone on each plate, and second, that the differences between the V-mA, V-mB, and V-mc vs. B-V or I-mA, I-mB’ I-m^ vs. V-I relations for each cluster and those established from the survey-system field standards can be ignored. F la t f ie ld p la te s were obtained in each f il t e r during each observing run. The flat field was supplied by the tw ilight sky or by scattered skylight near the moon. This allowed the entire system from telescope to plate to be included in the calibration. The plates obtained during the 1976 observing run were mapped with the two-axis scanning densitometer at Battelle Memorial Institute in Columbus, Ohio. Plates obtained during 1977 were reduced with a two-dimensional reticon array at Battelle Memorial Institute. Iso-sensitivity zone overlays were generated from the density maps and were used to divide the stars on each plate into iso -se n sitiv ity groups. These are groups of stars with images affected to the same extent by the photocathode se n sitiv ity variation. For each zone, the relationship between the iris measurement and pseudo-magnitude in the survey system was established. The pseudo-magnitudes PA, Pg, and Pg in the survey-system were extrapolated from the available B, V or V, I photometry for the clusters utilizing the following equations: PA = V - 1.334 - 0.294( B - V ) - 0.309( B - V )2 (3) PB = V - 1.213 - 0.236( B - V ) - 0.301( B - V )2 (4) Pc = V - 0.717 - 0.114( B - V ) - 0.531( B - V )2 (5) PA = I - 1.070 (6) 80 Pg = I - 1.000 (7) Pc = I - 0.240 - 0.463( V - I ) ( 8 ) Equations 3, 4 and 5 are the average relationships between the B, V photometry of Blanco et al . (1968) and survey-system photometry for survey-system standard sta rs. Equations 6, 7 and 8 are the average relationships between survey-system photometry for survey-system standard stars and the V, I photometry defined from Blanco et al (1968) V magnitudes and Kron et. a l. (1953) I magnitudes. This I magnitude is used by Lloyd Evans in his V, I photometry of globular clusters such as 47 Tuc. For each plate a least-squares polynomial was f it to the relation between the iris measurements and appropriate pseudo-magnitudes for all iso-sensitivity groups to determine the coefficents of the linear and squared terms instead of fitting to each zone seperately. This was done because the stars in each zone are not uniformly distributed along the iris versus pseudo-magnitude relationship for the plate. One zone may have only fain t sta rs, another only bright stars, and the polynomials fit to the different zones independently have different coefficents for the linear and squared terms because of the clumping and not because of intrinsic differences in the shapes of the polynomials for each zone. By fitting the polynomial to all zones at once, the coefficents determined for the linear and squared terms are the best values for all zones. To acheive th is, I have assumed a relationship between iris readings and pseudo-magnitude of the form: 2 (9) 81 where I„ . is the iris measurement for star s in zone i of s,i the plate, a^, and c.. are the coefficents of the equation for zone i of the plate, Pg is the pseudo magnitude for star s. I have further assumed that for all zones i on a plate, only the first coefficent of the equation is zone-dependent. That is a^ 4 - ag ^ a 2 • • • and b ^ — ^2 *"* ^ 3 * * * and c ^ ^2 ^ 3 * * * f o r the plate. With th is assumption all the zones can be brought together by correcting the iris reading as follows: I* = lSji + ( - a, ) (10) where I* is the corrected iris measurement for star s in s in the plate, is the average of all a^'s for the plate. The corrected iris readings for each cluster are given in Tables16 to 22. The efficacy of this technique is illustrated in Figures 19and 20 which are the iris readings plotted versus pseudo-magnitude "before" and "after" correction. The improvement of the data is quite dramatic. I have tried 1east-squares polynomials up to the cubic in a manner similar to that described for the quadratic above, but there was no noticeable improvement in results over those obtained with the quadratic, and the quadratic fitting was deemed sufficent. The curvature at the faint end in Figure 19 is introduced by an iris reading lim it which is set by the plate background. This limit also appears in the figure as a reduction in the scatter at the fa in t end because the lim it sets a minimum for the iris reading any star can 82 Table 16: 47 Tuc, Corrected Iris Readings. fnrrprtpd iris readings are given for each plate in each filte r. Star numbers are from Wildey (1961) and Lloyd Evans (1974) except for 99991 to 99993 which are identified on Figure 10. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 003 490. 490. 552. 432. 483. 533. 45 276 . 220 . 247 . 432. 483 . 4 02. 052 406 . 384. 411. 306 . 365 . 501. 055 36 4. 331. 360 . 270 . 323 . 433. 090 258. 222. 245. 270 . 328. 409 . 092 336 . 300 . 364 . 24 2. 308. 497 . 095 307. 258. 300 . 204. 270 . 44 3 . 107 481. 468. 524. 390 . 4 4 5. 537. 111 265. 224. 248. 163. 243. 418. 115 50 9 . 4 95. 561. 383. 434 . 609 . 139 387. 361. 381. 284. 3 56 . 515. 148 358. 322. 34 2. 267 . 327 . 493 . 149 218. 187 . 214. 141 . 206 . 391. 162 24 4 . 213. 232. 218. 218. 406 . 164 376 . 341 . 337 . 293. 350 . 531. 186 363. 5 38 . 330 . 276 . 351 . 507 . 212 549 . 553. 564. 446 . 487 . 607 . 213 337. 367 . 308. 286 . 352. 46 0 . 235 322. 282. 254 . 235 . 301. 424 . 237 4 96 . 46 9. 488. 363. 421. 553. 254 461. 4 54. 464 . 359. 40 7 . 548. 301 397 . 367 . 415 . 299. 367 . 525 . 302 424 . 397 . 448 . 316 . 379. 545 . 306 359. 322. 360 . 265. 330 . 494 . 307 347. 305. 335. 239. 311. 471. 309 419. 387 . 422. 332. 382. 516 . 310 314. 277 . 287 . 235. 315. 436 . 317 332. 283. 291. 237 . 299 . 436 . 318 414. 399 . 418. 338. 375. 493 . 331 292. 210 . 250 . 333 . 375. 44 0 . 3 34 265. 211. 208. 222. 279 . 381. 333 4 42. 432. 464. 336 . 338. 535 . 339 365. 312. 323. 253. 324. 46 3. 346 429. 417 . 432. 336 . 392. 520 . 351 46 9. 472. 439 . 367 . 4 30 . 564. 365 468 . 4 57 . 436 . 344 . 403 . 522. 367 403 . 370 . 333. 235. 361. 473 . 377 439. 413. 413. 337 . 397 . 525. 378 405. 384. 366 . 305. 371 . 507 . 379 372. 340 . 330 . 26 9. 336 . 476 . 384 442. 414. 435. 347 . 393. 539. 383 596 . 615. 705. 4 94. 555. 702 . 390 583. 610 . 706 . 481. 540 . 693. 391 441. 428. 0 . 347 . 407. 557 . 401 455. 4 39. 0 . 366 . 424. 565. 402 312. 26 7 . 301. 202. 277. 457 . 410 351. 322. 36 4 . 256 . 326. 486 . 411 463. 4 58. 511. 377 . 432. 570 . 409 486 . 493. 549. 380 . 448. 603 . 1001 548. 558. 634. 452. 512. 643 . 83 Table 16 (continued) STAR IRIS A IRIS IRIS IRIS A IRIS D IRIS 1002 535. 535 600 625. 6 96 . 629 1003 590 . 626 705 691. 566 . 687 10 06 585. . 605 702 696 . 555. 630 1005 696 . 6S6 521 383 . 652. 573 1006 502. 6 98 536 393 . 662 . 585 1007 576. 568 6 22 650 . 516 . 639 1003 560 . 571 577 620 . 699 . 622 1009 560 . 571 611 662. 512. 617 1010 562. 563 577 631. 692. 608 1011 502. 506 531 608 . 0 . 572 1012 565. 552 597 656 . 516. 622 1013 588. 669 7 65 671. 591. 736 1016 570 . 587 615 652. 529. 635 1016 56 6. 537 6 67 679. 527 . 670 1018 582. 603 683 6 96 . 558 . 637 1019 520 . 523 581 660 . 6 95 . 617 2002 615. 605 605 3 36. 379. 689 2003 561. 556 606 661. 500 . 600 2005 373. 356 36 3 275. 335 . 673 2006 512. 516 507 382. 665. 566 2007 687 . 633 500 395. 66 7. 552 2008 601. 636 707 501 . 563. 696 2009 503. 507 532 60 9. 659 . 532 2010 502. 506 560 612. 67 6 . 602 2011 568. 556 629 666. 517 . 667 2012 361. 317 321 261. 319. 669 99991 563. 56 3 666 655. 512. 661 99992 666. 637 662 363 . 626 . 560 99993 667 . 662 516 372. 626 . 569 VI 663. 729 806 578. 6 62. 765 V2 616 . 681 766 566 . 622. 739 V3 607 . 660 766 0 . 0 . 767 V 6 533. 607 719 6 36. 552. 699 V6 556 . 582 625 670 . 522. 619 V 7 562. 557 663 0 . 0 . 629 V8 66 9 . 698 785 555. 625. 762 Al 618. 668 762 501. 5 96 . 732 A2 599. 671 767 507 . 5 96 . 720 A 6 567 . 596 691 676 . 537 . 692 A6 506 . 556 637 6 07 . 503. 662 A9 573. 602 691 6 90 . 559. 693 A18 653. 711 803 533. 622. 787 A1 9 593 . 66 3 736 697 . 56 5. 707 R1 606 . 638 616 566 . 600 . 611 R2 637 . 650 710 516 . 587 . 710 R3 622. 661 672 518. 586. 689 R8 • 563. 581 638 673. 536 . 666 RIO 627 . 668 703 513. 576. 700 Rll 602. 626 685 696 . 551. 671 R23 573. 579 651 666. 516 . 653 84 T able 16 (c o n tin u e d ) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C R24 553. 566 . 662. 472. 530 . 650 . R26 596 . 623. 692. 513. 574. 700 . R36 551. 569. 652. 481. 532. 654 . R 38 504. 501. 505. 403 . 455. 548 . R51 628. 655. 711. 528. 5 93. 710 . R79 576 . 601. 669. 492. 552. 682. 85 Table 17: M5, Corrected Iris Readings. Corrected iris readings are given for each plate in each filte r. Star numbers are from Arp (1955) except for 5001 to 99992 which are identified on Figure 12. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS 1001 369 . 368. 371. 0. 0 . 0 . 1002 609 . 627. 602. 0 . 0 . 0 . 1003 370 . 365. 369. 0 . 0 . 0 . 10 0 4 663. 680. 663. 0. 0 . 0 . 1005 600 . 390 . 387 . 0 . 0 . 0 . 1008 362. 312. 356. 0. 0. 0. 1012 366 . 365. 378. 0 . 0 . 0 . 1014 511. 519. 507 . 0 . 0 . 0 . 1015 366 . 363 . 378. 0 . 0 . 0 . 1020 589. 578. 586 . 0 . 0 . 0 . 1021 399 . 601. 609 . 0. ' 0 . 0 . 1025 627 . 639. 660 . 0 . 0 . 0 . 1031 332. 325. 367 . 0 . 0 . 0 . 1035 378. 385. 391 . 0 . 0 . 0 . 1036 336 .• 333. 367. 0. 0. 0 . 1039 691. 691 . 501. 0 . 0 . 0 . 1060 362. 318. 363. 0 . 0. O'. 1063 392. 391. 606 . 0 . 0 . 0 . 1069 332. 327 . 352. 0 . 0 . 0 . 1050 610 . 605. 602 . 0 . 0 . 0 . 1055 616. 617 . 397 . 0 . 0 . 0 . 1056 336 . 311. 352. 0 . 0 . 0 . 1057 361. 331. 358. 0 . 0 . 0 . 1058 673. 686. 667 . 0 . 0 . . 0. 1059 359. 363. 368. 0 . 0 . 0 . 1061 660 . 667 . 657 . 0 . 0 . 0 . 1067 379. 331. 390 . 0 . 0 . 0 . 1068 ' 5 96. 589. 602. 0 . 0 . 0 . 1071 695. 697 . 505. 0. 0 . 0 . 1076 382. 385. 603. - 0. 0. 0. 1075 327 . 309. 356 . 0 . 0 . 0 . 1080 382. 376. 609. 0. 0. 0. 1081 613. 615. 622. 0 . 0 . 0 . 2001 366 . 363. 337 . 0 . 0. 0. 2007 326. 319. 329. 0 . 0 . 0 . 2009 599. 596. 532. 0 . 0 . 0 . 2012 336 . 337 . 325. 0 . 0 . 0 . 2018 371. 363 . 36 0 . 0 . 0. 0 . 2020 367 . 328. 325. 0 . 0 . 0 . 2026 376 . 361 . 352 . 0 . 0 . 0 . 2031 36 6. 332. 36 0 . 0 . 0 . 0 . 2039 36 9. 368 . 366 . 0 . 0 . 0 . 2065 360. 325. 330 . 0 . 0 . 0 . 2050 609 . 603. 363 . 0 . 0 . 0 . 2051 3S5. 392. 358. 0. 0 . 0. 2056 377 . 375. 363. 0 . 0 . 0 . 2059 676 . 689. 663 . 0 . 0 . 0 . 2061 661. 632. 618. . 0 . 0 . 0 . 2063 333. 320 . 361. 0. 0 . 0 . 2069 373. 371. 366 . 0 . 0. 0 . Table 17 (continued) IRIS B IRIS C IRIS A IRIS B IRIS C STAR IRIS A O C D O O O O O O O O O O O O O O O O O O O O O O O O O O C D O O O O O O O O O O O O O O C D O O O a O O 2074 4 08 . 415. 4 06. 0. 0. 2080 366 . 333. 363. 0. 0. 2085 613. 609 . 600 . 0. 0 . 2086 443. 453. 437. 0. 0. 2093 358. 358 . 369. 0. 0. 30 0 3 6 04. 597. 560. 0. 0. 3006 328. 322. 357. 0. 0. 3007 330 . 313. 365. 0. 0. 3009 334. 325. 343. 0. 0. 3012 349. 353. 373. 0. 0. 3013 328. 326 . 37 4. 0. 0. 3015 364 . 365. 381. 0. 0. 3016 358. 368 . 374. 0. 0. 3018 457 . 46 6 . 432. 0. 0. 3019 367 . 373. 379. 0. 0. 3024 407 . 410 . 380. 0. 0. 3026 368. 367 . 381. 0. 0. 3030 329. 314. 372. 0. 0. 3031 361. 358. 385. 0. 0. 3032 367 . 376 . 390. 0. 0. 3036 527 . 530 . 515. 0. 0. 3048 345. 346 . 370. 0. 0. 3 049 332. 317 . 363. 0. 0. 3050 509. 523. 488. 0. 0. 3052 378. 381. 390. 0. 0. 3053 411. 4 34. 411. 0. 0 . 3056 435. 455. 420. 0. 0. 3059 332. 396 . 387. 0. 0. 3062 351. 351. 366. 0. 0. 3066 370. 381. 382. 0. 0. 3067 433. 448. 427. 0. 0. 3078 550 . 554. 573. 0. 0. 4003 330 . 316 . 359. 0. 0. 4004 383. 386 . 339. 0. 0. 4006 343. 343. 359. 0. 0. 4010 368. 361. 360. 0. 0. 4011 387 . 390 . 335. 0. 0. 4012 437 . 440 . 437. 0. 0. 4019 550 . 557 . 577. 0. 0. 4022 334 . 324. 333. 0. 0. 4026 3 94. 404 . 412. 0. 0. 4028 354. 347 . 360. 0. 0. 4030 422. 435. 416. 0. 0. 4033 366 . 360 . 36 4. 0. 0. 4 0 34 475. 485. 502. 0. 0. 4035 341. 321 . 342. 0. 0. 4036 385. 383. 336. 0. 0. 4037 350 . 341. 34 9. 0. 0. 4040 34 0 . 336. 339. 0. 0. 4047 592. 598. 597. 0. 0. 87 Table 17 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 4 04 9 474. 487. 475. 0 . 0 . 4056 47 4. 489. 466 . 0 . 0 . 4059 534. 542 . 538. 0 . 0 . 4065 369. 363. 354. 0 . 0 . 4067 342. 335. 340 . 0 . 0 . 4072 508. 518. 520 . 0 . 0 . 4073 376 . 377 . 379. 0 . 0 . 4074 428. 438. 432. 0 . 0 . 4078 373. 371. 384. 0 . 0 . 4081 612. 615. 646 . 0 . 0 . 4082 44 2. 461 . 478. 0 . 0 . 5001 682. 676 . 674. 0 . 0 . 5002 461. 479. 453. 0 . 0 . 5003 4 43. 464. 4 35. 0 . 0 . 50 04 385. 4 04. 390 . 0 . 0 . 5005 413. 437 . 397 . 0 . 0 . 5006 326 . 315. 348. 0 . 0 . 5007 40 6 . 4 30. 393. 0. 0 . 5008 580 . 586 . 560 . 0 . 0 . 5009 520 . 536 . 524. 0 . 0 . 5010 374. 376. 335. 0 . 0 . 5011 384. 404 . 388. 0 . 0 . 5012 424 . 445. 417 . 0 . 0 . 5013 361. 36 9 . 365 . 0 . 0 . 5 0.14 346 . 341. 34 0 . 0 . 0 . 5015 36 3 . 379. 383. 0 . 0 . 5016 477. 497 . 472. 0 . 0 . 5017 452. 473. 44 0 . 0 . 0 . 5018 623. 631. 614. 0 . 0 . 5019 547. 556 . 510 . 0 . 0. 5020 363. 367 . 365. 0 . 0 . 5021 592. 595. 541. 0 . 0 . 5022 663. 657 . 621. 0 . 0 . 5023 504. 528. 483. 0 . 0 . 5024 382. 399. 381. 0 . 0 . 5025 329. 325. 0 . 0 . 0 . 99991 554. 413. 525. 0 . 0 . 99992 384. 373. 391. 0 . 0 . OOOOOC3C3000C3C300COC30000C900000000000000C30 88 Table 18: M10, Corrected Iris Readings. Corrected iris readings are given for each plate in each filte r. Star numbers are from Arp (1955) and Harris, Racine and De Roux (1975). STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 1002 765. 702 . 707. 0. 0 . 0. 10 04 350 . 346 . 365. 0 . 0 . 0 . 1009 419. 443 . 4 34 . 0 . 0 . 0 . 1013 364. 356 . 368. 0 . 0 . 0 . 1015 541. 560 . 553. 0 . 0 . 0 . 1018 464. 478 . 490 . 0 . 0 . 0 . 1023 336 . 320 . 354. 0 . 0 . 0 . 1024 448. 470 . 484 . 0 . 0 . 0 . 1025 514. 520 . 531 . 0 . 0 . 0 . 1028 359. 357 . 333. 0 . 0 . 0 . 1035 456 . 43 0 . 48 0 . 0 . 0 . 0 . 1039 360 . 375 . 393. 0 . 0 . 0 . 1042 447 . 465. 486 . 0 . 0 . 0 . 1043 333. 305 . 355. 0 . 0 . 0 . 1044 330. 287 . 354 . 0 . 0 . 0 . 1048 393. 404 . 4 34 . 0 . 0 . 0 . 1049 373 . 333 . 397 . 0 . 0 . 0 . 1054 319. 285. 341. 0 . 0 . 0 . 1055 332. 317 . 360 . 0 . 0 . 0 . 1056 434. 4 43. 478. 0 . 0 . 0 . 1057 328. 304 . 354. 0 . 0 . 0 . 1060 492. 522. 537 . 0 . 0 . 0 . 1061 514. • 517 . 529. 0 . 0 . 0 . 1063 3 94 . 408 . 410. 0 . 0 . 0 . 1069 33 0 . 306 . 362. 0 . 0 . 0 . 1070 353. 411. 450 . 0 . 0 . 0 . 1076 335. 303 . 366 . 0 . 0 . 0 . 1078 355. 331. 379. 0 . 0 . 0 . 2002 419. 419. 418. 0 . 0 . 0 . 2007 348. 325. 344. 0 . 0 . 0 . 2011 332. 390 . 399 . 0 . 0 . 0 . 2015 405. 403 . 397 . 0 . 0 . 0 . 2024 761 . 689. 685. 0 . 0 . 0 . 2032 337 . 374 . 373. 0 . 0 . 0 . 2036 50 4. 502 . 484. 0 . 0 . 0 . 2037 45 0 . 447 . 437. 0 . 0 . 0 . 2043 329. 325. 355. 0 . 0 . 0 . 2046 34 2. 317 . 34 6 . 0 . 0 . 0 . 2049 373. 394 . 402. 0 . 0 . 0 . 2050 640 . 612. 614 . 0 . 0 . 0 . 2052 381. 398 . 401. 0 . 0 . 0 . 2053 327 . 296 . 332. 0 . 0 . 0 . 2057 37 4 . 371. 378. 0 . 0 . 0 . 2060 345. 338. 351 . 0 . 0 . 0 . 2065 348. 330 . 352. 0 . 0 . 0 . 2067 365. 366 . 379. 0 . 0 . 0 . 2068 382. 399. 398. 0 . 0 . 0 . 2071 314. 290 . 34 0 . 0 . 0 . 0 . 2072 638. 604 . 590 . 0 . 0 . 0 . 2074 390 . 410 . 396. 0 . 0 . 0 . Table 18 (c o n tin u e d ) STAR IRIS A IRIS B IRIS IRIS A IRIS B IRIS C 2076 485. 491. 482 0 . 0 . 0 . 2079 324 . 315. 332 0 . 0 . 0 . 2032 327 . 233 . 315 0 . 0 . 0 . 2083 351 . 319. 336 0 . 0 . 0 . 2085 386 . 376 . 378 0 . 0 . 0 . 2086 326 . 316 . 338 0 . 0 . 0 . 2087 34 7 . 340 . 344 0 . 0 . 0 . 2091 318. 280 . 317 0 . 0 . 0 . 2094 339. 548 . 359 0 . 0 . 0 . 2095 344. 335. 350 0. 0. 0. 2093 407 . 416 . 406 0 . 0 . 0 . 2101 0 . 311 . 330 0 . 0 . 0 . 2103 330 . 306 . 326 0 . 0 . 0 . 2104 480 . 437 . 452 0 . 0 . 0 . 2105 536 . 561. 543 0. 0 . 0 . 3002 474. . 492. 463 0 . 0 . 0 . 30 04 348 . 338. 358 0 . 0 . 0 . 3005 590 . 577 . 568 0 . 0 . 0 . 3006 356 . 341. 36 4 0 . 0 . 0 . 3008 343. 315. 349 0 . 0 . 0 . 3016 684. 649. 651 0 . 0 . 0 . 3019 365. 344 . 371 0 . 0 . 0 . 3021 763. 690 . 697 0 . 0 . 0 . 3022 346 . 338 . 340 0 . 0 . 0 . 3023 344 . 326 . 346 0 . 0 . 0 . 3026 355. 329. 343 0 . 0 . 0 . 3027 332 . 324. 354 0 . 0 . 0 . 3028 493 . 491. 429 0 . 0 . 0 . 3029 526 . 527 . 511 0 . 0 . 0 . 3033 353. 350 .. 359 0 . 0 . 0 . 3034 399 . 423. 401 0 . 0. 0 . 3038 344 . 336 . 367 0 . 0 . 0 . 3040 340 . 333 . 361 0 . 0 . 0 . 3046 34 9. 355 . 361 0 . 0 . 0 . 3047 371. 381. 381 0 . 0 . 0 . 3053 446 . 441. 416 0. 0 . 0 . 3054 489. 490 . 4 52 0 . 0 . 0 . 3055 555. 541. 508 0 . 0 . 0 . 3056 423. 433. 414 0 . 0 . 0 . 3059 362 . 363. 379 0 . 0 . 0 . 3077 341. 344 . 368 0 . 0 . 0 . 3080 320 . 303 . 350 0 . 0 . 0 . 3081 423. 451. 426 0 . 0 . 0 . 3033 34 3 . 318 . 359 0 . 0 . 0 . 3085 564. 557 . 528 0 . 0 . 0 . 3088 341. 328 . 380 0 . 0 . 0 . 3090 344. 325. 362 0 . 0 . 0 . 3091 490. ' 499. 506 0 . 0 . 0 . 3092 370. 398. 403 0 . 0 . 0 . 3093 550 . 542. 555 0 . 0. 0 . Table 18 (c o n tin u e d ) STAR IRIS A IRIS B IRIS :s a IRIS B IRIS C 3095 336 . 314. 381 o. 0 . 0 . 3099 334. 366 . 395 o . 0 . 0 . 4001 370 . , 330 . 362 o . 0 . 0 . 40 04 4 09 . 414. 429 0 . 0 . 0 . 4005 351. 335. 377 0 . 0 . 0 . 4006 37 4. 369. 395 0 . 0 . 0 . 4008 481. 497 . 497 0 . 0 . 0 . 4014 343. 322. 356 0 . 0 . 0 . 4015 6 32 . 611. 611 0 . 0. 0 . 4017 427 . 443. 4 35 0 . 0 . 0 . 4019 414. 414. 416 0 . 0 . 0 . 4020 409 . 418. 431 0 . 0 . 0 . 4023 454. 459. 458 0 . 0 . 0 . 4025 373. 408 . 420 0 . 0 . 0 . 4029 373. 379 . 393 0 . 0 . 0 . 4030 571. 570 . 570 0 . 0 . 0 . 4036 352. 341. 375 0 . 0 . 0 . 4040 333. 310 . 366 G . 0 . 0 . 4044 712. 661 . 636 0 . 0 . 0 . 404 5 371. 383 . 381 0 . 0 . 0 . 4049 367 . 367 . 376 0 . 0 . 0. 4050 362. 356 . 357 0 . 0 . 0 . 4053 346 . 332. 367 0 . 0 . 0 . 4054 445 . 470 . 475 0 . 0 . 0 . 4059 4 41 . 462. 472 0 . 0 . 0 . 4061 346 . 337 . 334 0. 0 . 0. 4064 401. 377 . 0 0 . 0 . 0 . 4067 369. 377 . 383 0 . 0 . 0 . 4068 366 . 369 . 382 0 . 0 . 0 . 407 9 356 . 364 . 390 0 . 0 . 0 . 4 082 36 6 . 337 . 366 0 . 0 . 0 . 4085 408 . 426 . 449 0 . 0 . 0 . 4086 495. 508. 521 0 . 0 . 0 . 4087 387 . 4 06 . 421 0 . 0 . 0 . 20001 353. 327 . 369 0 . 0. 0. 20002 319. 301 . 34 6 0 . 0 . 0 . 20044 738. 675. 685 0 . 0. 0 . 20053 341. 321. 363 0 . 0 . 0 . 20059 361. 346 . 363 0 . 0 . 0 . 20060 332. 333. 394 0 . 0. 0 . 20079 355. 334 . .328 0. 0. 0. 20103 380 . 381 . 373 0 . 0 . 0 . 20106 344. 332. 327 0 . 0. 0 . 20115 341 . 313. 333 0 . 0 . 0 . 20135 332. 313. 357 0. 0. 0 . 20139 397 . 401. 390 0 . 0 . 0 . 20154 377 . 387 . 399 0 . 0 . 0 . 20161 550. 562. 560 0. 0. 0. 20163 341. 318. 365 0 . 0 . 0 . 20217 567 . 576 . 581 0 . 0 . 0 . Table 18 (continued) STAR IRIS A IRIS B IRIS C IRIS A IRI 20213 457. 475. 434. 0 . 20224 399. 396. 414. 0. 20249 353. 343. 377. 0. 20000 659. 619. 602. 0. 92 Table 19: M12, C o rre c te d I r i s R eadings. Corrected iris readings are given for each plate in each filte r. Star numbers are from Racine (1975) except for 21901 21902, 31901, 41901, 41902, and 90001 to 90018 which are all identified on Figure 14. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS c 11001 595. 601. 552. 0 . 0 . 0 . 11002 723. 726 . 727. 0. 0 . 0 . 11016 546 . 556 . 502. 0. 0 . 0 . 11017 4 45. 426 . 397 . 0 . 0 . 0 . 11045 395. 380 . 398 . 0 . 0 . 0 . 11048 469. 478. 443. 0 . 0 . 0 . 11051 379. 342. 378. 0 . 0 . 0 . 11056 439. 415. 401. 0 . 0 . 0 . 11065 330 . 343. 377 . 0. 0 . 0 . 11067 443. 427 . 409. O'. 0 . 0 . 12005 365. 339. 34 0 . 0. 0 . 0 . 12025 545. 556 . 478 . 0 . 0 . 0 . 12042 484. 502. 424. 0 . 0 . 0 . 12046 383. 363. 351. 0 . 0 . 0 . 12049 394 . 339. 353. 0 . 0 . 0 . 12058 377 . 356 . 377 . 0 . 0 . 0 . 12065 525. 552. 432 . 0 . 0 . 0 . 12062 340 . 629 . 356 . 0 . 0 . 0 . 12070 556 . 571 . 492. 0 . 0 . 0 . 12086 470. 490. 463. 0 . 0 . 0 . 12091 4 46 . 457 . 423. 0 . 0 . 0 . 12096 374. 367 . 376 . c . 0 . 0 . 21004 401. 376 . 371. 0 . 0 . 0 . 21007 622. 635 . 613. 0 . 0. 0 . 21010 400 . 3S7. 368. 0 . 0 . 0. 21016 560 . 585. 572. 0 . 0 . 0 . 21028 361. 341. 343 . 0 . 0 . 0 . 21030 392. 365 . 350 . 0 . 0 . 0 . 21033 405. 393. 394 . 0 . 0 . 0 . 21036 397. 374. 383. 0 . 0 . 0 . 21038 533. 549. 512. 0 . 0 . 0 . 21041 337 . 357 . 369. 0 . 0 . 0 . 21044 376 . 356 . 368. 0 . 0 . 0 . 21048 373. 354. 363 . 0. • 0 . 0 . 210 54 874. 356 . 871. 0 . 0 . 0 . 21055 469 . 449. 417 . 0 . 0 . 0 . 21057 381. 365. 365. 0 . 0 . 0 . 21063 534. 545. 513. 0 . 0 . 0 . 21067 383. 377 . 386 . 0 . 0 . 0 . 22004 354. 342. 369. 0 . 0 . 0 . 22014 465. 465. 480 . 0 . 0 . 0 . 22032 419. 415. 406 . 0 . 0 . 0 . 22047 602. 627. 606 . 0 . 0 . 0 . 22051 587 . 601. 562. 0 . 0 . 0 . 22054 4 08. 395 . 395 . 0 . 0 . 0 . 22055 429. 416 . 406 . 0 . 0 . 0 . 22063 542. 545 . 487 . 0 . 0 . 0 . 22065 400 . 395. 402. 0 . 0 . 0 . 22072 365. 34 2. 379 . 0 . 0 . 0 . 22073 376 . 366 . 389. 0 . 0 . 0 . Table 19 (c o n tin u e d ) ris c IRIS IRIS STAR IRIS A IRIS B : IRIS A OOOOOOOOOOOOOOCDCDOOOCDOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO 31003 44 4. 435. 425. 0 . 0 . 31006 424. 420 . 393 . 0 . 0 . 31007 36 6 . 335. 352. 0 . 0 . 31009 462 . 473. 437 . 0 . 0 . 31013 452. 441. 431. 0 . 0 . 31021 457. 467. 4 42. 0 . 0 . 31023 353. 337 . 362. 0 . 0 . 31026 448. 438. 421. 0 . 0 . 31028 468. 464. 467 . 0 . 0 . 31033 383. . 376 . 378. 0 . 0 . 31037 434 . 427 . 405. 0 . 0 . 31052 374 . 353. 366 . 0 . 0 . 32022 359. 337 . 369 . 0 . 0 . 32023 410. 413. 411. 0 . 0 . 32025 428. 409 . 3 94 . 0 . 0 . 32037 3 93'. 372. 393. 0 . 0 . 32039 416 . 406 . 413. 0 . 0 . 32056 404. 390 . 398. 0 . 0 . 410 0 9 462. 476 . 415. 0 . 0 . 41018 541. 553. 48 0 . 0 . 0 . 41020 626 . 633. 570 . 0 . 0 . 41024 661. 675 . 6 48. 0 . 0 . 41031 485. 492. 428 . 0 . 0 . 41035 4 06 . 367 . 351 . 0 . 0 . 41042 429. 401. 354. 0 . 0 . 41055 383. 372. 352. 0 . 0 . 41070 384 . 34 4. 359 . 0 . 0 . 41076 618. 622. 591 . 0 . 0 . 41073 444. 459. 422. 0 . 0 . 42009 372. 353. 359. 0 . 0 . 42039 409. 4 07 . 421. 0 . 0 . 42063 487 . 510 . 469. 0 . 0 . 42037 365. 350 . 37 6 . 0 . 0 . 42010 637. 692. 710. 0 . 0 . 12901 4 04 . 408 . 400 . 0 . 0 . 12903 366 . 343. 376 . 0 . 0 . 21901 741. 742. 744 . 0 . 0 . 21902 564. 583. 551 . 0 . 0 . 31901 3 94. 368. 374. 0 . 0 . 41901 586 . 595. 54 9 . 0 . 0 . 41902 772. 781. 62. 0 . 0 . 90001 729. 742 . 751 . 0 . 0 . 90002 586 . 602. 590 . 0 . 0 . 90003 6 37. 650. 596 . 0 . 0 . 9 0 0 0 4 628. 639 . 595 . 0 . 0 . 90005 543. 549. 47 3. 0 . 0 . 90006 599. 610. 571 . 0 . 0 . 90007 631. 641. 614. 0 . 0 . 90008 6 05. 619. 525. 0 . 0 . 90009 7 00 . 711. 672. 0 . 0 . T able 19 (c o n tin u e d ) STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS 90010 536. 565. 500. 0. 0. 0 90012 608. 626. 580. 0. 0. 0 90013 699. 698. 639. 0. 0. 0 90016 686. 690. 629. 0. 0. 0 90015 688. 561. 692. 0. 0. 0 90016 509. 50 6. 639. 0. 0. 0 90017 685. 631. 626. 0. 0. 0 90018 515. 506. 668. 0. 0. 0 95 Table 20: M92, C o rre c te d I r i s R ead in g s. Corrected iris readings are given for each plate in each filte r. Star numbers are from Sandage and Walker (1966) except for 13001 to 13015 which are identified on Figure 15. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 1013 328. 329. 347 . 0 . 0 . 0 . 1014 338. 333. 363. 0 . 0 . 0 . 1040 338. 339. 342. 0 . 0 . 0. 1067 47 7 . 479. 446 . 0 . 0 . 0 . 1068 330 . 331. 363 . 0 . 0 . 0 . 2012 353. 340 . 362. 0 . 0 . 0 . 2024 351 . 34 9. 361. 0 . 0 . 0 . 2028 311. . 310 . 334 . 0 . 0 . 0 . 2039 358. 365. 381. 0 . 0 . 0 . 2053 6 04 . 539. 576 . 0 . 0 . 0 . 2070 501 . 4 98 . 482. 0 . 0 . 0 . 2089 373. 384. 378 . 0 . 0 . 0 . 2120 337 . 341. 343. 0 . 0 . 0 . 2121 400 . 407 . 393. 0 . 0 . 0 . 3011 316 . 314. 333. 0 . 0 . 0 . 3013 672. 655. 671 . 0 . 0 . 0 . 3065 601 . 590 . 591. 0 . 0 . 0 . 3081 339. 347. 355. 0 . 0 . 0 . 3082 479. 474 . 44 9 . 0 . c . 0 . 3088 320 . 321. 345. 0 . 0 . 0 . 3096 315. 306 . 333 . 0 . 0 . 0 . 3098 333. 339. 34 7 . 0 . 0 . 0 . 3109 312. 311. 340 . 0 . 0 . 0 . 40 02 448 . 435. 436 . 0 . 0 . 0 . 4010 446 . 443. 436 . 0 . 0 . 0 . 4040 391. 3 90 . 375. 0 . 0 . 0 . 4079 461 . 461 . 421. 0 . 0 . 0 . 4087 306 . 303 . 329. 0 . 0 . 0 . 4094 503. 504 . 477. 0 . 0 . 0 . 5045 54 3. 533. 502 . 0 . 0 . 0 . 5069 334 . 332. 340 . 0 . 0 . 0 . 5078 34 9. 341. 341. 0 . 0 . 0 . 5106 601 . 533 . 566 . 0 . 0 . 0 . 6013 411. 411. 372. 0 . 0 . 0 . 7010 423. 414. 569 . 0 . 0 . 0 . 7018 648. 625. 590. 0 . 0 . 0 . 7039 34 8. 344. 360 . 0 . 0 . 0 . 7067 328. 333. 34 7 . 0 . 0 . 0 . 7068 363. 366 . 37 4. 0 . 0 . 0 . 707 9 366 . 378. 370 . 0 . 0 . 0 . 7 08 0 401. 398. 379. 0 . 0 . 0 . 7122 614. 597 . 565. 0 . 0 . 0 . 8024 384. 375. 364 . 0 . 0 . 0 . 8012 327 . 322. 330 . 0 . 0 . 0 . 8043 336 . 332. 361 . 0 . 0 . 0 . 8044 383. 382 . 377 . 0 . 0 . 0 . 9012 334. 320 . 34 3. 0 . 0 . 0 . 9013 395. 398. 369. 0 . 0 . 0 . 9030 371 . 367 . 377 . 0 . 0 . 0 . 9049 402. 396 . 37 4. 0 . 0 . 0 . Table 20 (c o n tin u e d ) STAR IRIS A IRIS D IRIS IRIS A IRIS B IRIS C 9077 374. 367. 370 0 . 0 . 0 . 9089 378. 376 . 37 4 • 0. 0 . 0 . 10 049 623. 608 . 583 0 . 0 . 0 . 10065 361. 356 . 36 4 0 . 0 . 0 . 10028 338. 338. 369 0 . 0 . 0 . 11014 410 . 415. 403 0 . 0 . 0 . 11019 539. 528. 466 0 . 0 . 0 . 11027 33 9. 346 . 369 0 . 0 . c . 11038 339 . 343. 357 0 . 0 . 0 . 12007 326 . 329. 363 0 . 0 . 0 . 12008 538. 527. 486 0 . 0 . 0 . 12018 335. 342. 351 0 . 0 . 0 . 12031 393. 3S8 . 393 0 . 0 . 0 . 12034 453. 453. 430 0 . 0 . 0 . 12045 379. 383. 389 0 . 0 . 0 . 13001 322. 328 . 338 0 . 0 . 0 . 13002 362. 363. 386 0 . 0 . 0 . 13003 620 . 601 . 60S 0 . 0 . 0 . 13005 518. 511 . 4 57 0 . 0 . 0 . 13006 603. 592 . 546 0 . 0 . 0 . 13007 633. 607 . 571 0 . 0. 0 . 13008 592. 582. 536 0 . 0 . 0 . 13009 606 . 602 . 54 3 0 . 0 . 0 . 13010 657 . 639. 611 0 . 0 . 0 . 13011 6 43 . 626 . 600 0 . 0 . 0 . 13012 573. 562. 529 0 . 0 . 0 . 13013 384 . 392. 401 0 . 0 . 0 . 13 0 0 4 499. 495. 444 0 . 0 . 0 . 13014 398. 40 9 . 370 0. 0 . 0 . 13015 373. 337 . 385 0 . 0 . 0 . 97 Table 21: NGC 6397, Corrected Iris Readings. Corrected iris readings are given for each plate in each filte r. Star numbers are from Woolley et al, (1961) except for 901 to 903 which are identified on Figure 16. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 043 490 . 457. 580 . 567. 563. 570. 99 514 . 432. 539. 611. 608 . 586 . 128 342. 295. 400 . 402. 4 33 . 4 35. 132 295. 24 9 . 326 . 327 . 372. 370 . 139 24 0 . 194. 261 . 272. 302. 292 . 140 297 . 26 4. 328. 364 . 391. 37 6 . 143 223. 185. 246 . 285 . 309 . 301. 144 417. 373. 449 . 4 97 . 500 . 479 . 158 408. 377 . 453. 48 9. 505 . 481. 179 459. 422. 499 . 539. 549 . 535. 164 292. 215. 315. 339. 36 6 . 369. 194 311. 264. 3 34 . 374. 383. 385. 193 321. 294. 370. 386. 424 . 4 09 . 199 339. 298. 376 . 390 . 420 . 418. 205 303.. 248. 337 . 361. 0 . 380 . 208 434 . 399 . 509. 527 . 558 . 533. 235 3 94. 361. 459. 489. 507 . 467 . 251 472. 437. 552. 580 . 58 7. 547 . 265 318. 272. 34 5 . 379 . 425. 402. 278 365. 315. 391. 4 27 . 467 . 434 . 281 435. 404. 481. 542. 550 . 526 . 283 4 90 . 448. 54 3. 602. 613. 571. 285 327 . 275. 354 . 382. 405. 396. 288 253. 198 . 266 . 288 . 323 . 321 . 291 529. 497 . 595. 652. 659 . 610 . 296 442. 417 . 433. 542. 563 . 526 . 318 523. 490 . 57 9. 6 34 . 634 . 601. 323 300 . 255 . 335 . 371. 400 . 390 . 330 308. 263. 339 . 377 . 406 . 390 . 347 346 . 0. 372. 420 . 436 . 0 . 353 377 . 324. 411 . 450 . 4 66 . 4 36 . 354 392. 337 . 441 . 4 82 . 4 96 . 461. 357 287 . 256 . 316 . 347 . 36 4 . 367 . 359 401. 358. 4 37 . 482 . 501 . 4 66 . 364 239. 197. 261. 289. 299. 313. 368 303 . 256 . 328. 362. 382. 376 . 375 476 . 443 . 516 . 576 . 585. 545. 376 352. 305 . 377 . 419. 439. 421 . 386 363. 319. 384 . 447 . 459 . 431. 387 486 . 464. 54 0 . 60 9 . 610. 567 . 392 2 94 . 230 . 310 . 34 7 . 373. 361 . 393 265. 214. 285 . 321 . 34 5 . 325. 394 297. 255. 331 . 367 . 382. 365 . 397 380 . 341. 412. 453. 462. 439. 404 390 . 348 . 424. 462. 481. 457 . 4 08 322 . 279. 353 . 387 . 409. 395. 411 4 02 . 364. 4 35. 490 . 4 96 . 476 . 417 321. 283. 335. 389. 402. 389 . 420 330 . 287 . 352. 392. 412. 390 . 422 353. 324. 427 . 406 . 443. 466 . 98 Table 21 (continued) STAR IRIS A IRIS B IRIS IRIS A IRIS B IRIS C 625 576 . 536. 679 680 . 680 . 656 . 628 637 . 600 . 507 517 . 533 . 516 . 636 300 . 269. 353 337 . 392 . 388. 65 9 668 . 631. 521 567 . 567 . 555. 668 665. 609. 6 97 519. 536 . 517. 669 596 . 566 . 6 9 9 697 . 703. 690 . 67 3 382. 333 . 607 662. 659 . 66 0 . 676 612. 375. 6 32 680 . 6 90 . 668 . 679 332. 336. 600 657. 663. 630 . 686 282. 232. 260 327 . 36 0 . 305 . 501 390 . 368 . 616 673. 687 . 660 . 503 316 . 263. 312 380 . 387 . 370 . 511 631. 600 . 672 515. 535 . 500 . 519 286 . 233. 309 36 5. 369 . 353. 521 228. 173. 230 272 . 296 . 268. 555 326 . 286 . 351 396. 628 . 606 . 56 6 36 0 . 298. 363 606 . 625. 600 . 565 372. 325. 609 66 3. 655. 6 38. 566 623. 333. 667 675 . 521 . 677 . 576 320 . 275 . 330 383. 391. 359 . 575 376. 329 . 395 632. 652. 626. 603 567 . 535. 660 661 . 678. 666 . 605 339 . 291. 356 392. 628. 3 99. 901 600 . 370 . 636 692. 503. 669. 902 668. 633. 683 576. 586 . 532. 903 557 . 520 . 619 651. 667 . 639. 99 Table 22: NGC 6752, Corrected Iris Readings. Corrected iris readings are given for each plate in each Ini' J? a r numbers are from Alciano (1972) except for 901 to 911 which are identified on Figure 17. STAR IRIS A IRIS B IRIS C IRIS A IRIS B IRIS C 001 384 . 425. 456 . 0 . 0 . 418. 002 353. 400 . 420 . 0 . 0. 368. 0 03 431. 471. 501 . 0 . 0 . 481. 008 429. 472. 498. 0 . 0 . 491. 009 500 . 533. 573 . 0 . 0 . 578. 010 313. 365 . 371. 0 . 0 . 330. 011 353. 399. 420 . 0 . 0 . 387. 012 506 . 541. 596 . 0 . 0 . 593. 016 54 3. 594. 651. 0 . 0 . 647. 018 527. 564. 622. 0 . 0 . 614. 019 290 . 342. 375 . 0 . 0 . 326 . 029 435. 469. 503. 0. 0 . 475. 030 381. 414. 443. 0. 0 . 407 . 031 547 . 585. 670 . 0 . 0 . 665. 033 419.. 0 . 461. 0 . 0 . 253. 0 34 338 . 390 . 430 . 0 . 0 . 374. 035 376 . 4 34 . 478 . 0. 0. 44 9. 036 463. 493. 547 . 0 . 0 . 540 . 0 42 474. 506 . 562. 0 . 0 . 567 . 043 338. 425. 47 4. 0 . 0 . 470 . 044 472. 513. 559. 0 . 0 . 553. 045 472. 510 . 559. 0 . 0 . 5 54. 046 290 . 344 . 399. 0 . 0 . 350 . 048 299 . 344. 404 . 0 . 0 . 387 . 055 383. 423. 476 . 0 . 0 . 451. 058 330 . 373. 413 . 0 . 0 . 359. 059 54 0 . 58 5. 634. 0 . 0 . 641 . 060 337 . 383. 430 . 0 . 0 . 337 . 061 468. 504. 547 . 0 . 0 . 532. 063 299. 369 . 402. 0 . 0 . 360 . 068 415. 458 . 504. 0 . 0 . 479 . 069 279. 339. 344. 0 . 0 . 278. 070 346. 393. 465. 0 . 0 . 413. 077 332. 373. 412. 0 . 0 . 357 . 038 537 . 579. 626 . 0 . 0 . 625. 092 303. 356 . 384. 0 . 0 . 314. 104 325. 377 . 396 . 0 . 0 . 341. 105 404. 452. 480 . 0 . 0 . 441 . 113 386 . 431. 451 . 0 . 0 . 414. 140 3 34. 333. 412. 0 . 0 . 375. 159 274. 335. 371. 0 . 0 . 325. 160 422. 47 5. 508. 0 . 0 . 501 . 210 325. 385. 425. 0 . 0 . 372. 212 465. 501. 551 . 0 . 0 . 0 . 238 431 . 517 . 560 . 0 . 0 . 548. 251 514. 54 9. 599 . 0 . 0 . 593. 275 500 . 535. 587 . 0 . 0 . 573. 276 435. 474. 521 . 0 . 0 . 498 . 281 354. 399. 44 4 . 0 . 0 . 406 . 284 482. 504 . 563. 0 . 0 . 556 . 100 Table 22 (c o n tin u e d ) STAR IRIS A IRIS B IRIS C IRIS A IRIS B 301 330 . 379. 616. 0 . 0 . 367 . 302 285. 338. 367 . 0 . 0 . 308. 308 300 . 358. 397 . 0 . 0 . 361 . 319 331. 375. 611. 0 . 0 . 356 . 323 633. 0. 561. 0 . 0 . 56 3. 326 359. 602. 636 . 0 . 0 . 398 . 327 258. 322. 352. 0 . 0 . 281. 336 380 . 639. 667. 0 . 0. 665. 901 376. 622. 668. 0 . 0 . 606 . 902 56 9. 597 . 636. 0 . 0 . 616. 903 351. 601. 635. 0 . 0 . 389. 906 263. . 328. 363. 0 . 0 . 303. 905 503. 566 . 569. 0 . 0 . 533. 906 397 . 651. 673. 0 . 0 . 666 . 907 336. 389. 626 . 0 . 0 . 376. 903 656. 507 . 536. 0 . 0 . 509. 909 655. 506 . 525. 0 . 0 . 506. 910 651. 683. 539. 0 . 0 . 533. 911 573. 617. 666. 0 . 0 . 669 . 101 7 00 boo 500 Hoo • 1*1 30 0 Figure 19: Uncorrected filte r C iris readings (Ir ) plotted versus filte r C pseudo-magnitudes (Pc ) for stars in M92. 700 £00 500 *«••••••H • • • M •« « •• • • i • »•* « •• Mai | I 500 Figure 20: Corrected filte r C iris readings (I *) plotted versus filte r C pseudo-magnitudes (Pc) for stars in M92. 103 have. Therefore the fainter stars are omitted from the polynomial fitting since they contain almost no information about the brightnesses of stars. A cutoff of faint stars for the polynomial fitting is made by inspection of figures for each plate like Figure 19, and is set at the point where the iris reading versus pseudo-magnitude relationship becomes noticeably non-linear. 3.4 PHOTOELECTRIC OBSERVATIONS There are two main purposes for obtaining photoelectric survey-system photometry of stars in the eight globular clusters. First, photoelectric photometry of some stars in each field is required to convert the iris readings to magnitudes. Second, i t is desirable to obtain photoelectric photometry of the C and M stars found in the photographic survey to verify their nature and to improve their classifications. The majority of the photoelectric observations in northern globular clusters were obtained with the Perkins 72-inch telescope of the Ohio State and Ohio Wesleyan Universities which is located at the Anderson Mesa site of Lowell Observatory. These observations were made in the Spring of 1977 and 1978 with the equipment described in section 2.3.1. Some additional observations were made in the Fall of 1978 with the 50-inch telescope at Kitt Peak National Observatory during an observing run with Dr. Wing. The purpose of that run was to establish a 104 set of faint eight-color standards for use with the new Varian tube which has a quantum efficiency 30 times greater than that of an S-l tube. These eight-color observations were converted to the survey system using the relationships between the two systems derived in section 2.2. The photoelectric observations in clusters which were too far south to be observed from Flagstaff were obtained with the 36-inch telescope at Cerro Tololo Inter-American Observatory in the Summer of 1978. The photoelectric data are summarized in Table 23. Not all eight clusters were observed because of observing time constraints and weather problems. Long integration times were required because of the faintness of the stars and the low sensitivity of the S-l tube. Because of the need to obtain a reasonable sample of stars in each clu ster, the integration times were lim ited and the results for the fainter stars are based on single observation totals of only about 300 counts. For the brighter stars, about 2000 counts were obtained per observation. The accuracy of the photoelectric data is thus limited by photon s ta tis tic s . Because of the smaller telescope used at CTI0, the limiting magnitude for photoelectric observations was brighter ( V _< 12.5 ) than the limit for observations with the Perkins 72-inch ( V < 14). 105 Table 23: Photoelectric Survey-System Photometry of Globular Cluster Stars. Cluster Star A B C Date Telescope Where 47 Tuc 2008 8..61 8..48 8.49 6-25-78 36-inch CTIO V4 8. .59 8. .24 8.13 6-25-78 36-inch CTIO oo Cen 29 9..58 9. 0 0 CO 9.89 6-25-78 36-inch CTIO M5 1068 10.,07 10..12 10.38 5-17-77 72-inch Lowel1 10.,03 10.,07 10.26 5-17-77 72-inch Lowel1 10.,12 10..19 10.39 5-18-77 72-inch Lowel1 10.,05 10.,13 10.31 5-19-77 72-inch Lowel1 1061 11.,27 11.,30 11.49 5-17-77 72-inch Lowel1 11.,04 11.,08 11.35 5-17-77 72-inch Lowel1 11.,20 11.,42 11.82 5-18-77 72-inch Lowel1 1055 11.,66 11.,76 12.04 6-16-78 72-inch Lowel1 1067 11.,82 12..08 12.55 5-17-77 72-inch Lowel1 4006 12.,27 12..37 12.17 5-17-77 72-inch Lowel1 12.,29 12. ,35 12.44 5-18-77 72-inch Lowel1 2061 11.,43 11.,44 11.54 5-16-77 72-inch Lowel1 11.,19 11. ,45 5-17-77 72-inch Lowel1 1057 12.,89 12.,89 13.09 5-17-77 72-inch Lowel1 12.,68 12.,68 13.42 5-19-77 72-inch Lowel1 13.,17 13.,04 14.35 5-18-77 72-inch Lowel1 4059 10.,45 10.,34 10.80 5-18-77 72-inch Lowel 1 10.,46 10.,54 10.79 5-19-77 72-inch Lowel1 10.,45 10.,49 10.58 5-17-77 72-inch Lowel1 1058 10.,99 11.,08 11.55 5-19-77 72-inch Lowel1 11.,03 11.,08 11.20 5-18-77 72-inch Lowel 1 2080 12.,18 12.,22 12.51 5-19-77 72-inch Lowel1 1035 12.,00 12.,19 12.53 5-18-77 72-inch Lowel1 M12 41024 9.,82 9.,85 9.97 6-15-78 72-inch Lowel1 9. ,92 9. ,96 10.14 6-16-78 72-inch Lowel1 11016 10.,81 10.,94 11.36 6-15-78 72-inch Lowel1 10.,97 10.,94 11.01 6-16-78 72-inch Lowel1 31003 11.,52 11.,84 11.14 6-15-78 72-inch Lowel1 11.,61 11.,75 11.23 6-16-78 72-inch Lowel1 11002 9.,31 9.,27 9.36 6-15-78 72-inch Lowel1 11001 10.,49 10.,59 10.50 6-15-78 72-inch Lowel1 12042 11.,46 11.,43 11.60 6-16-78 72-inch Lowel1 M92 4040 11.,83 12.,09 12.18 6-15-78 72-inch Lowel1 11.,94 11.,91 11.90 6-16-78 72-inch Lowel1 5045 10.,67 10.,68 6-16-78 72-inch Lowel1 10.,75 10.,79 11.05 6-15-78 72-inch Lowel1 10.,74 10.,78 11.08 9-13-78 50-inch KPNO 3065 10.,21 10.,31 10.64 6-15-78 72-inch Lowel 1 10.,24 10.,31 10.55 6-16-78 72-inch Lowel1 106 Table 23 (continued) Cl uster Star A B C Date Telescope Where M92 3065 10.14 10.36 10.78 6-16-78 72-inch Lowel1 7018 9.96 9.98 10.22 6-18-78 72-inch Lowel1 10.06 10.08 10.24 9-12-78 50-inch KPNO 10.26 9-13-78 50-inch KPNO 4010 11.34 11.58 11.90 6-18-78 72-inch Lowel1 11.40 11.58 11.70 6-18-78 72-inch Lowel1 7010 11.77 11.70 12.46 6-18-78 72-inch Lowel1 11.92 11.82 12.37 6-18-78 72-inch Lowel1 11.58 11.63 12.25 9-13-78 50-inch KPNO 12.21 9-12-78 50-inch KPNO 6018 11.70 11.57 12.20 6-18-78 72-inch Lowel1 11.95 12.20 12.26 9-13-78 50-inch KPNO NGC 6397 99 8.49 8.48 8.75 6-22-78 36-inch CTIO 8.48 8.49 8.70 6-25-78 36-inch CTIO 144 9.64 9.63 9.79 6-22-78 36-inch CTIO 9.70 9.68 10.01 6-25-78 36-inch CTIO 251 8.81 8.77 9.05 6-22-78 36-inch CTIO 8.81 8.79 9.06 6-25-78 36-inch CTIO 425 7.72 7.82 7.95 6-25-78 36-inch CTIO 428 9.37 9.39 9.66 6-22-78 36-inch CTIO 9.40 9.38 9.68 6-25-78 36-inch CTIO 469 7.48 7.50 7.62 6-22-78 36-inch CTIO 479 10.03 10.10 9.78 6-22-78 36-inch CTIO 10.29 9.98 10.27 6-25-78 36-inch CTIO 603 8.06 8.08 8.30 6-22-78 36-inch CTIO 8.09 8.09 8.28 6-25-78 36-inch CTIO NGC 6752 9 9.07 9.15 9.41 6-22-78 36-inch CTIO 9.06 9.15 9.41 6-25-78 36-inch CTIO 16 8.61 8.39 8.39 6-25-78 36-inch CTIO 31 8.28 8.34 8.47 6-22-78 36-inch CTIO 8.33 8.36 8.45 6-25-78 36-inch CTIO 36 9.39 9.52 9.63 6-22-78 36-inch CTIO 59 8.40 8.45 8.57 6-22-78 36-inch CTIO 8.43 8.41 8.54 6-22-78 36-inch CTIO 8.41 8.41 8.58 6-25-78 36-inch CTIO 68 9.88 9.90 10.23 6-22-78 36-inch CTIO 911 8.26 8.30 8.45 6-25-78 36-inch CTIO 107 3.5 CALIBRATION OF THE PHOTOGRAPHIC PHOTOMETRY Figures 21 through 25 and Table 24 show the calibrations of the plates for each of the clusters for which sufficient photoelectric observations were made to establish a photoelectric sequence. The scatter around the mean in each figure is about +_ 10 in iris units for clusters with single plates in each filter, and about +_ 6 for clusters where the averaged corrected iris reading is based on two plates in each filter. These numbers convert to approximately +_ 0.08 and _+ 0.05 magnitudes, respectively. The relationships in Table 24 are useful only in the regime where iris readings are lin early related to magnitudes, since at the faint end, curvature isintroduced in the relationship because of the plate limit, and the iris readings for these faint stars will not give good magnitudes. The calibration given in Table 24 for 47 Tuc was bootstrapped since I did not obtain sufficient photoelectric survey-system photometry to determine it directly. The bootstrap procedure consisted of three steps: (1) Available 8-color photoelectric photometry in filters 3, 4 and 5 for a number of stars in 47 Tuc (Wing, unpublished) which are outside the area covered by my plates were converted to survey-system magnitudes (m^, mg, and m^) using the relationships between the two systems established in section 2.3.2. (2) I found that the mean relationships between m^, mg, m^ and the V, I photometry of Lloyd Evans (1974) for the same stars agreed quite well with the relationships established from the survey-system standard stars in 600 600 - 500 -WO I HOO 3oo Figure 21: Corrected filter A, B and C iris readings (I. , IR , I q ) plotted versus photoelectric survey-system magnitudes (mA, mB, mc) for stars in M5. 109 7Cp SCo- HDb 4CO m ★ ★ Figure 22: Corrected filter A, B and C iris readings (I. , In , Ir ) plotted versus photoelectric survey-system magnitudes (mA, mB, mc) for stars in M12. 110 100 500 6 0 0 5 0 0 HOO Figure 23: Corrected filter A, B and C iris readings (I. , I * Ip ) plotted versus photoelectric survey-system magnitudes (mA, mB, mc) for stars in M92. 700 100 mA’ mB’ mC Figure 24: Corrected filter A, B and C iris readings (I * I * Iq ) plotted versus photoelectric survey-system magnitudes (mA, mB, mc) for stars in NGC 6397. 112 7 0 0 • • bOO Hoo zoo Figure 25: Corrected filter A, B and C iris readings (I * I * Ip ) plotted versus photoelectric survey-system magnitudes (mA, mB, mc ) for stars in NGC 6752. Table 24: Calibration Equations to Convert Iris Readings to Magnitudes. Equation is of the form: m = a.. - b.I Cluster F i1 ter Magnitude Limit ai bi 47 Tuc A 13.64 0.00927 12.0 B 13.55 0.00837 12.0 C 14.60 0.00866 12.0 M5 A 15.29 0.00870 12.0 B 15.29 0.00870 12.0 C 15.04 0.00800 12.0 M12 A 15.78 0.00897 12.0 B 15.93 0.00897 12.0 C 14.83 0.00752 12.0 M92 A 15.06 0.00803 11.8 B 15.20 0.00830 11.8 C 15.28 0.00826 11.8 NGC 6397 A 14.79 0.01124 10.5 B 14.67 0.01136 10.5 C 15.23 0.01091 10.5 NGC 6752 A 14.59 0.01131 10.5 B 15.24 0.01163 10.5 C 14.82 0.00935 10.5 114 equations 6, 7 and 8 (section 3.3.2). (3) I established the iris-magnitude relationships between the pseudo survey-system magnitudes derived from the V, I photometry using equations 6, 7 and 8 and the averaged corrected iris readings IA , Ig and Ig which produced the bootstrap calibration given in Table 24 for 47 Tuc. Photographic magnitudes have been calculated from the relationships given in Table 24 for the six clusters that could be calibrated. They are listed in Tables 25 to 30 along with TiO and CN indices calculated from the magnitudes with equations 1 and 2. I have plotted the TiO and CN indices versus mg for the clusters in Figures 26 to 31. The use of these TiO/CN diagrams for the detection of C and M stars will be described in detail in section 4.1. There are systematic and random errors visible in these diagrams. The systematic errors are most visible in the TiO/CN diagrams for M5 and M12 as sharp changes in the slopes of the bands across the middles of Figures 27 and 28. The coefficients in Table 24 were derived for the brighter stars which appear to follow a linear iris-magnitude relationship, while curvature at the faint end of the iris-magnitude relationship, as described in section 3.3.2, was ignored so that the magnitudes calculated for the faint stars are systematically in error. The amount of curvature is different in each filter for a cluster and the systematic errors are therefore different for each filter. What is happening in M5 and M12 is that the filte r A magnitudes bottom out before the filte r B magnitudes and the CN indices appear stronger in fainter stars. It would be possible to determine non-linear 115 Table 25: 47 Tuc, Photographic Survey-System Magnitudes and Indices. STAR MAG A MAG B MAG C TIO CN 003 9.37 9.48 9.66 0.0 0.08 045 0.0 0.0 0.0 0 . 0 0.0 052 10.34 10.42 10.65 0.0 0.04 055 10.70 10.80 10.93 0.0 0.06 090 11.19 11.25 11.77 0.02 0.0 0 92 10 . 96 11.01 10.87 0.0 0.06 095 11.27 11.34 11.38 0.0 0.06 107 9.60 9.73 9.79 0.0 0.11 111 11.63 11.60 11.72 0.05 0.0 115 9.43 9.67 9.53 0.0 0 .18 139 10.53 10.55 10.72 0 .00 0.0 148 10.74 10.84 10.96 0.0 0.07 149 11.98 11.91 11.98 0 . 03 0.0 162 ...... 11.50 11.73 11.84 0.0 0.18 164 10.54 10.66 10.84 0.0 0.08 186 10.66 10.67 10.98 0 . 03 0.0 212 9.03 9.20 9.53 0.0 0.11 213 10.52 , 10.54 11.27 0.08 0 . 0 235 11.06 11.11 11.66 0.03 0 . 0 237 9.66 9.83 10.07 0.0 0.12 254 9.84 9. 95 10 .22 0 . 0 0.06 301 10.41 10.48 10.53 0.0 0.05 302 10.21 10.31 10.30 0.0 0.08 306 10.75 10 .82 10 . 90 0.0 0.06 307 10 . 92 10 . 98 11.10 0.0 0.03 309 10.16 10.34 10.54 0.0 0.13 310 11.10 11.08 11.47 0.08 0.0 317 11.00 11.12 11.45 0.0 0.06 318 10.15 10.31 10.66 0.0 0.10 331 10 .72 11.10 11.61 0.0 0.27 334 11.38 11.50 12.05 0.0 0 .03 338 10.03 10.12 10.27 0.0 0 . 06 339 10 .78 10 .89 11.20 0 . 0 0.06 346 10.09 10.17 10.48 0.0 0 .02 351 9.77 9.78 10.04 0.02 0.0 365 9.88 9.96 10.45 0.0 0.00 367 10.45 10.49 11.09 0.05 0.0 377 10.04 10.14 10.54 0.0 0.04 378 10.35 10 .39 10.82 0.02 0.0 379 10.67 10.72 11.11 0.00 0.0 384 9. 98 10 .18 10.38 0.0 0.14 383 8.59 8.66 8.51 0.0 0.08 390 8.71 8.74 8.52 0.0 0.06 391 9.99 10.06 0.0 0.0 0.0 401 9.83 9. 94 0 . 0 0.0 0.0 402 11.26 11.28 11.32 0.0 0.01 410 10 .83 10 .84 10.92 0.0 0.00 411 9.75 9.83 9.92 0.0 0.06 409 9.63 9.62 9.61 0.01 0.0 1001 9.01 9. 08 9.07 0 . 0 0 . 06 116 Table 25 (continued) STAR MAG A MAG B MAG C TIO CN 1002 9.19 9.24 9.28 0.0 0.04 1003 .. 8.63 8.58 8.57 0.05 0.0 1004 8.64 8.70 8.62 0.0 0.07 1005 9.54 9.63 9.86 0 . 0 0. 04 1006 9.49 9.54 9.75 0.0 0.01 1007 8.89 9.02 9.14 0.0 0.09 1003 9.10 9. 08 9.41 0.07 0 . 0 1009 9.00 9.02 9.28 0.01 0.0 1010 9.13 9.22 9.47 0.0 0.05 1011 9.42 0.0 9.82 0.0 0.0 1012 9.00 9.09 9.32 0.0 0.05 1013 8.73 8.28 8.19 0 .43 0.0 1014 8.90 8.89 9.19 0.06 0.0 1016 8.81 8.89 8. 90 0.0 0.08 1018 8.64 8.70 8.67 0.0 0.05 1019 9.19 9.29 9.41 0 . 0 0. 08 2002 10.17 10.27 10.73 0.0 0.03 2003 9.09 9.14 9.39 . 0.0 0.02 2005 10.62 10.67 11.07 0.01 0.0 2006 9.50 9.53 9.95 0.03 0.0 2007 9.55 9.66 10.04 0.0 0.05 2008 8.53 8.55 8.53 0.0 0.01 2009 9.41 9.51 9.78 0.0 0.05 2010 9.40 9.45 9.57 0.0 0.03 2011 8. 95 9.06 9.07 0.0 0.10 2012 10 .85 10.89 11.18 0.00 0 . 0 99991 9.01 9. 06 9.04 0 . 0 0 . 04 99992 9.80 9.95 10.17 0.0 0.10 99993 9.75 9.85 9.90 0.0 0.08 VI 7.89 7.82 7.80 0.07 0.0 V 2 8.25 8.10 8.17 0 .16 0.0 V3 0.0 0.0 8.05 0.0 0.0 V4 9.16 8.71 8.46 0.42 0.0 V6 8.88 8.94 9.21 0.0 0 . 01 V7 0.0 0.0 9.01 0 . 0 0.0 V8 8. 06 8.02 7.90 0.02 0.0 A1 8.45 8.27 8.22 0.17 0.0 A2 8.51 8.26 8.25 0.25 0.0 A4 8.81 8.81 8.61 0.0 0.03 A6 9.42 9.12 8.98 0.27 0.0 A9 8.71 8.70 8.59 0.0 0.00 A18 8.14 7.98 7.72 0.13 0.0 A19 8.56 8.50 8.36 0.04 0.0 RI 8.31 8.38 9.29 0.07 0.0 R2 8.50 8.08 8.45 0 . 0 0.06 R3 8.36 8.43 8.71 0.0 0.03 R8 8.79 8.8S 8.96 0.0 0.07 RIO 8.36 8.44 8.53 0.0 0.06 Rll 8.55 8.64 8.73 0.0 0.06 R23 8.83 8. 97 8.95 0.0 0.12 117 Table 25 (c o n tin u e d ) STAR MAG A MAG B MAG C TIO CN R24 8.89 8.97 8.92 0.0 0.08 R26 8.50 8.55 8.57 0.0 0.04 R36 8.86 8. 95 8.95 0.0 0.08 R38 9.44 9.55 10.04 0.0 0.04 R51 8.28 8.31 8.45 0.0 0.01 R79 ...... 8.69 8.73... 8.75..... 0.0 0.03 Table 26: M5, Photographic Survey-System Magnitudes and Indices. STAR MAG A MAG B MAG C TIO CN 1001 12.02 12.13 11.99 0 . 0 0.11 1002 11.72 11.68 11.74 0 . 05 0 . 0 1003 12.06 12.22 12.06 0 . 0 0 .16 1004 11.20 11.15 11.47 0 .10 0.0 1005 11.75 11. 93 11. 92 0.0 0.16 1008 12.26 12.62 12.18 0 . 0 0 . 37 1012 12. 07 12.16 12.17 0.0 0 . 08 1014 10.79 10.81 11.14 0.03 0.0 1015 12.07 12.17 12.17 0 .0 0.09 1020 10.11 10.30 10.50 0 . 0 0 .14 1021 11.76 11.84 11.92 0 . 0 0 . 05 1025 11.43 11.44 11.67 0.02 0.0 1031 12.26 12.44 12.26 0.0 0.18 1035 11 .86 11.91 12.06 0 . 0 0.03 1036 12.31 12.43 12.26 0 . 0 0.13 1039 10 . 96 11.05 11.18 0 . 0 0 . 06 1040 12.26 12.56 12.29 0 . 0 0.30 1043 11.82 11.92 11 . 96 0 . 0 0 . 08 1049 12.34 12.4S 12.38 0.0 0.13 1050 11.67 11.80 11.98 0.0 0 .10 1055 11.63 11.70 11.84 0.0 0 .04 1056 12.31 12.63 12.20 0 . 0 0.33 1057 12.27 12.45 12.33 0 . 0 0 . 18 1058 11.12 11.11 11.46 0 . 05 0.0 1059 12.11 12.34 12.25 0.0 0.21 1061 11.23 11.26 11.54 0.01 0 . 0 1(36 7“'’ 1T.93"" 12.01 12. 07 0 . 0 0 .06 1068 10. 06 10.20 10.38 0.0 0.10 1071 10 . 93 11.00 11.15 0 . 0 0.05 1074 11 .82 11. 91 11 .97 0 . 0 0 . 07 rors “ 12730 T275B "■ 12.34 0 . 0 0.27 1080 11.82 12.01 11 . 92 0 . 0 0 .18 1081 11.64 11.71 11.82 0.0 0.05 2001 12.11 12.24 12.04 0 . 0 0 .14 ' 2007‘ . 12.41"" 12. 56 ' 12.17 " (T. 0 0.18 2009 10.02 10.17 10.54 0 . 0 0.08 2012 12.31 12.40 12.14 0.0 0.12 2018 12.00 12.18 12.02 0 . 0 0.17 2 02 (3 1272 T" ' 12 . 4"S '" 12 720 0.0 ' 0.27 2024 11.96 12.18 11.98 0.0 0.22 2031 12.24 12.44 12.24 0 . 0 0 .20 2039 12. 02 12.13 12.03 0 . 0 0.11 ' 2045 . ■ \ 2 .2 7" " 12.51 12.16' 0.0 0 .25 2050 11.67 11.83 11.90 0 . 0 0 .12 2051 11.88 11.92 11.94 0 . 0 0 .03 2054 11.95 12.06 12.02 0 . 0 0 .10 ... i r ; o r - "2059 r r. tra .11.42 0.06 0 . 0 2061 11.40 11.58 11.62 0 . 0 0.15 2063 12.38 12.61 12.23 0.0 0.25 . 2069 11.99 12.10 12.03 0.0 0.10 [ 119 Table 26 (continued! STAR MAG A MAG B MAG C TIO CN 2074 11.63 11.68 11.79 0 . 0 0 . 03 2080 12.00 12. 39 12.10 0 . 0 0.38 2085 9.85 • 9.99 10 .24 0 . 0 0.09 2086 11.33 11.35 11.54 0.01 0 . 0 2093 12.07 12.18 12.09 0.0 0 .11 3003 9. 93 10.10 10.56 0 . 0 0.09 3006 12.33 12.49 12.18 0 . 0 0 .18 3007 12.31 12.57 12.12 0.0 0.28 3009 12.27 12.46 12.26 0.0 0 .19 3012 12.14 12.22 12. 02 0 . 0 0 .09 3013 12.33 12.45 12. 05 0 . 0 0.16 3015 12. 01 12.11 11.99 0.0 0 .10 3016 12.07 12.09 12.05 0 . 0 0 . 03 3018 11.20 11.24 11 .58 0 .02 0 . 0 3019 11.99 12. 04 12.01 0 . 0 0 .06 3024 11.64 11.72 12.00 0 . 0 0.04 3026 11.98 12.10 11. 99 0 . 0 0 . 12 3030 12.32 12.56 12. 06 0 . 0 0 .27 3031 12.04 12.18 11. 96 0 . 0 0 .15 3032 11.99 12.02 11. 92 0.0 0.04 3036 10.60 10.68 10.92 0 . 0 0.04 3048 12.18 12.28 12. 08 0 . 0 0.11 3049 12.29 12.53 12.14 0 . 0 0 .26 3050 10.75 10.74 11.14 0 .07 0 . 0 3052 11.89 11.98 11.92 0 . 0 0.08 3053 11.60 11.51 11.75 0 .13 0 . 0 3056 ' 11.40 11.33 11.68 " 0.12 0 . 0 3059 11.86 11.84 11. 94 0 .03 0 . 0 3062 12.13 12.24 12.11 0 . 0 0 .11 3066 11. 96 11. 98 11. 98 0 . 0 0.01 3067 ' 11.37"' 11.39 ' 11.62 "0.01 ' 0 . 0 3078 10.40 10.47 10.46 0.0 0.07 4003 12.31 12.54 12.17 0 . 0 0.25 4004 11.85 11.93 11. 93 0 . 0 0.07 4006 12.15 "12.31 12.1/ 0 . 0 0 .15 4010 11.98 12.15 12.16 0.0 0.15 4011 11.81 11.90 11.96 0.0 0.06 4012 11 .38 11.46 11.54 0 . 0 0.06 4019 10.40 10.44 10.42' 0 . 0 0 . 05 4022 12.27 12.47 12.34 0.0 0.19 4026 11.75 11.78 11.74 0 . 0 0.02 4028 .12.10 12.27 12.16 0 . 0 0 .16 4030 11.51 11.51 11.71 ' 0 .03 .....0.0 4033 12.00 12.16 12.13 0 . 0 0 .15 4034 11.05 11.07 11.02 0 . 0 0.03 4035 12.21 12.50 12.30 0 . 0 0 .27 4036 11 .83 11. 96 11.95 0 . 0 0.11...... 4037 12.14 12.32 12.25 0 . 0 0.17 4040 12.22 12.37 12.33 0.0 0.13 4047 10.03 10.09 10.26 0 . 0 0.03 l Table 26 (c o n tin u e d ) STAR MAG A MAG B MAG C TIO CN 4049 11.06 11. 05 11.24 0 .03 0.0 4056 11.06 11 .04 11.31 0 . 06 0.0 ' 4059 10.53' 10.57 10.74 0 . 0 0.01 4065 11 . 97 12.13 12.21 0 . 0 0 .13 4067 12.20 12.38 12.32 0 . 0 0 .16 4072 10.76 10 . 78 10 .88 0 . 0 0.01 4073 11.91 12.01 12.01 0.0 0.09 4074 11.46 11.48 11.58 0 . 0 0.01 4078 11.93 12.06 11.97 0 . 0 0 . 12 4081 9.86 9. 94 9.87 0.0 0 . 08 4082 11.33 11.23 11.22 0 . 05 0 . 0 5001 9.25 9.41 9.65 0 . 0 0.11 5002 11.17 11.12 11.42 0.09 0.0 5003 11.28 11 .25 11.56 0 .07 0 . 0 5 0 0 4 11.83 11. 78 11. 92 0 . 08 0 . 0 5005 11.59 11.49 11.86 0.15 0.0 5006 12.34 12.55 12.26 0 . 0 0 .22 5007 11.65 11.55 11.90 0 .15 0.0 5 0 03 10.13 10.19 10 .56 0 . 0 0.00 5009 10.66 10.63 10 .85 0 . 06 0. 0 5010 11.93 12.02 11. 96 0.0 0 .09 5011 11.84 11 . 78 11. 94 0.09 0 . 0 S oT S"" 11.49 "' 11.42 11.70 0 .12 0 . 0 5013 12.04 12. 08 12.12 0 . 0 0.03 5014 12.17 12.32 12.32 0 . 0 0 .13 0 . 0 5015 12. 02 11. 99 11 . 94 ... .00 ._ ir02 5016 11.03 10.-9 7 11 .26 0 . 0 5017 11.25 11.17 11.52 0.12 0 . 0 5018 9.76 9.80 10.13 0.01 0 . 0 5019 10 .42 10.45 10.96 0 . 04 0.0 5020 12.02 12.10 1 2 .12 "0.0 0 . 06 5021 10.03 10.11 10.71 0 .01 0.0 5022 9.37 9.57 10.07 0.0 0 .11 5023 10.30 10.70 11. 18 0 .17 0.0 5024 11.86 11.82 11.99 '' 0.06' " 0 . 0 5025 12.32 12.46 0.0 0.0 0.0 99991 10.36 11.65 10.84 0.0 1.23 99992 11.84 12. 04 11. 91 0.0 0 .20 Table 27: M12, Photographic Survey-System Magnitudes and Indices. STAR MAG A MAG B MAG C TIO CN 11001 10 .44 10 .54 10.68 0 . 0 0.07 11002 9.29 9.42 9. 36 0 . 0 0.11 ' l r o r r - ' 1'0.85“ 10 . 94 ""11.05 0 . 0 0.04 11017 11.79 12.11 11 .84 0 . 0 0.31 11045 12.24 12.52 11 .84 0.0 0.34 11048 11.57 11.64 11.50 0.0 0 . 08 H D '5 1 12.38 12.86 ' 11.99 0 . 0 0 .53 11056 11.84 12.21 11.81 0 . 0 0.37 11065 12.37 12.81 11. 99 0 . 0 0.49 11067 11.81 12.10 11.75 0 . 0 0.30 1200b '"I2.51“ ....12.89 12.2/ 0 . 0 0.41 12025 10.89 10.94 11.24 0.0 0.01 12042 11.44 11.43 11.64 0.04 0.0 12046 12.34 12.67 12.19 0.0 0 .35 12049 12:'2b"" 12.44 ' 12.18" 0 . 0 0.20 12058 12.40 12.74 11.99 0.0 0.39 12065 11.07 10 . 98 11.21 0 .13 0 .0 12062 12.73 10 .29 12.15 2.72 0 . 0 1 2 0 /0 “ 10 . / 9 10.81 11.15 0.05 0 . 0 12086 11.56 11 .53 11.35 0.00 0.0 12091 11.78 11.83 11.65 0.0 0 . 07 12096 12.43 12.64 12.00 0 . 0 0 .27 210 04 '" '12 . is~ 12.56 12.04 0.0 0 . 59 21007 10.20 10 .23 10 .22 0 . 0 0 .03 21010 12.19 12.46 12. 06 0 . 0 0 .28 21016 10.76 10.68 10.53 0 . 05 0 . 0 21028 '..12 r5"4 ""12.8/ 12.21 U . 0 0.5/ 21030 12.26 12.66 12.20 0.0 0 .40 21033 12.15 12.36 11 .87 0 . 0 0.25 21036 12.22 12.53 11.95 0 . 0 0.39 2 1'0 3 8" "117 0 0 ' 1 1 . U1 “ TO . '95 u . u 0.01 21041 12.31 12.73 12.06 0.0 0 .45 21044 12.41 12.74 12. 06 0.0 0.37 21048 12.43 12.75 12.10 0.0 "0.36 21054" / . 9'* 8.25 8.28 ' U . 0 " 0.2/ 21055 11.57 11.90 11.69 0.0 0 .31 21057 12.36 12.66 12.09 0.0 0.33 21063 10.99 11.04 10 . 97 0 . 0 0 .05 21067 ' 1 2 T 3 4 “ 12.55 ' 11. 93"” u . u 0.20 22004 12.60 12.86 12.06 0.0 0 .33 22014 11.61 11.76 11.22 0 . 0 0.20 22032 12.02 12.21 11.78 0 . 0 0 .22 '22 0 47 - 10 . 08 10.31 1U . 27 0.07' U . 0 22051 10.51 10 .54 10.60 0 . 0 0.01 22054 12.12 12.39 11.86 0.0 0.30 22055 11. 93 12.20 1111.78 .1?.. 0.0 0.29 22063' 10. 92" 11.04" u. 0 0.09 22065 12.19 12.39 11.81 0.0 0 .24 22072 12.51 12.86 11 . 98 0.0 0.42 22073 12.41 12.65 11. 90 0.0 0 .31 Table 27 (c o n tin u e d ) STAR MAG A MAG B MAG C TIO CN 31003 11.80 12.03 11.63 0 . 0 0 .25 31006 11.98 12.16 11.87 0 . 0 0.20 "310 0 7 ...12.30 12.93 ' 12."18 0 . 0 0.47 31009 11.64 11.69 11.54 0 . 0 0.06 31013 11.73 11.97 11.59 0 . 0 0 .27 31021 11.68 11.74 11.51 0 . 0 0 . 08 "31 O'23 12.5/ I2T9I 12.11 0 . u 0 .413 31026 11.76 12. 00 11.66 0 . 0 0 .25 31028 11.58 11.77 11.32 0.0 0 .22 31033 12.34 12.56 11.99 0 . 0 0 .26 3103/ ..11". 8 9 ' 127113 11. /a 0 . 0 0 .23 31052 12.43 12.76 12.08 0.0 0 .38 32022 12.56 12.91 12.06 0 . 0 0.41 32023 12.10 12.23 11.74 0 . 0 0 .17 3'2'0"Z~b 11.94 "12.26 "11.8/ 0 . 0 0 . 33 32037 12.25 12.59 11.87 0 . 0 0.39 32039 12. 05 12.29 11.72 0 . 0 0 .28 32056 12.16 12.43 11.84 0 . 0 0.32 410 0“9 ' TT.5' STAR MAG A MAG B MAG C TIO CN 90010 10. 97 11.04 11. 07 0 . 0 0.06 90012 10 . 33 10.33 10 .47 0.01 0.0 90013 11.3d 11.46 11.53 0 . 0 0.13 90014 11.42 11.53 11.60 0 . 0 0.09 90015 11.40 10 . 90 11.13 0 .54 0 . 0 90016 11.21 11.41 11 .53 0 . 0 0 . 15 9001 7 11.43 11.62 11.63 0 . 0 0.16 90018 11.16 11.39 11.46 0.0 0.19 I Table 28: M92, Photographic Survey-System Magnitudes and Indices. STAR MAG A MAG B MAG C TIO CN 1013 12.43 12.47 12.41 0.0 0.04 1014 12.35 12.44 12.28 0.0 0 .10 1040 12.35 12.39 12.46 0 . 0 0.03 1067 11.23 11.22 11.60 0.06 0.0 1068 12.41 12.45 12.28 0.0 0 .06 2012 12.23 12.38 12.29 0 . 0 0 .14 2024 12.24 12.30 12.30 0 . 0 0 . 05 2028 12.56 12.63 12.52 0 . 0 0.07 2039 12.19 12.17 12.13 0.01 0 . 0 2053 10.21 10 .31 10.52 0 . 0 0 . 06 2070 11.04 11. 07 11.30 0.00 0.0 2089 12.02 12.01 12.16 0 . 03 0.0 2120 12.35 12.37 12.41 0 . 0 0.01 2121 11.85 11.82 12.03 0 . 06 0 . 0 3011 12.52 12.59 12.53 0.0 0 . 07 3013 9.66 9.76 9.74 0 . 0 0.09 3065 10 .23 10.30 10.40 0 . 0 0 . 05 3081 12.34 12.32 12.35 0 .02 0 . 0 3082 11.21 11.27 11.57 0 . 0 0 .01 3088 12.49 12.54 12.43 0 . 0 0 .05 3096 12.53 12.66 12.53 0.0 0 .13 3098 12.39 12.39 12.41 0.00 0.0 3109 12.55 12.62 12.47 0 . 0 0.07 4002 11.46 11.59 11.68 0.0 0 .10 4010 11.48 11.52 11.68 0 . 0 0 . 02 4040 11.92 11.96 12.18 0 . 0 0.01 4079 11.36 11.37 11.80 0 . 05 0.0 4087 12.60 12.69 12.56 0 . 0 0.09 4094 11. 02 11. 02 11.34 0 . 05 0 . 0 5045 10.70 10 .78 11.13 0 . 0 0 .02 5069 12.38 12.44 12.47 0.0 0 .05 5078 12.26 12.37 12.46 0.0 0.09 5106 10 .23 10.36 10.60 0 . 0 0.08 6018 11.76 11.79 12.21 0.03 0 . 0 7010 11.66 11.76 12.23 0 . 0 0 .03 7018 9.86 10.01 10.41 0.0 0 .08 7039 12.27 12.34 12.31 0.0 0.07 7067 12.43 12.44 12.41 0.0 0.01 7068 12.15 12.16 12.19 0 . 0 0.01 7079 12.12 12.06 12.22 0 . 08 0 . 0 7080 11.84 11.90 12.15 0.0 0 .02 7122 10.13 10.24 10.61 0 . 0 0.05 8024 11. 98 12. 09 12.27 0 . 0 0.07 8012 12.43 12.53 12.55 0 . 0 0 . 08 8043 12.36 12.44 12.30 0 . 0 0.09 8044 11.98 12.03 12.17 0 . 0 0.02 9012 12.38 12.54 12.45 0 . 0 0 .16 9013 11.89 11. 90 12.23 0 .04 0 . 0 9030 12. 08 12.15 12.17 0 . 0 0.06 9049 11.83 11.91 12.19 0.0 0.03 125 Table 28 (continued)1 STAR MAG A MAG B MAG C TIO CN 9077 12.06 12.15 12.22 0 . 0 0.08 9089 12. 02 12.08 12.19 0 . 0 0.03 10049 10.06 10 .15 10.46 0 . 0 0.04 10065 12.16 12.25 12.27 0 . 0 0.07 10028 12.35 12.39 12.23 0 . 0 0.06 11014 11.77 11.76 11. 95 0 . 04 0 . 0 11019 10.73 10.82 11.43 0 .01 0 . 0 11027 12.34 12.33 12.23 0.0 0.00 11038 12.34 12.35 12.33 0.0 0 .02 12007 12.44 12.47 12.28 0.0 0 .05 12008 10 .74 10 .83 11.27 0.0 0 . 02 12018 12.37 12.36 12.38 0 .01 0.0 12031 11.90 11.98 12. 03 0 . 0 0 .06 12034 11.42 11.44 11.73 0 .03 0.0 12045 12.02 11. 98 12.07 0 . 05 0 . 0 13001 12.47 12.48 12.49 0 . 0 0.00 13002 12.15 12.15 12. 09 0.0 0 .00 13003 10 . 08 10 .21 10.26 0 . 0 0.11 13005 10.90 10.96 11.51 0.02 0 . 0 13006 10 .22 10.29 10.77 0.00 0.0 13007 9. 98 10.16 10.56 0.0 0.11 13008 10.31 10.37 10.85 0 .01 0.0 13009 10.19 10 .20 10.79 0 . 08 0 . 0 13010 9.78 9.90 10.23 0.0 0.05 13011 9. 90 10.00 10.32 0 . 0 0.05 13012 10.46 10.54 10.91 0 . 0 0.02 13013 11.98 11.95 11.97 0 .03 0.0 13004 11.05 11.09 11.61 0 .04 0 . 0 13014 11.86 11.81 12.22 0.12 0.0 13015 12.06 11.99 12.10 0.09 0.0 126 Table 29: NGC 6397,1 Photographic Survey-System Magnitudes and Indices. STAR MAG A MAG B MAG C TIO CN 043 8.85 8.88 8.89 0. 0 0.02 ... 99 8.47 8.48 8.77 0.03 0.0 128 10.61 10.53 10 .49 0.07 0.0 132 11.29 11.14 11.20 0.16 0.0 139 11. 91 11.85 11. 92 0.07 0.0 . 140 11.08 10.95 11.16 0. 16 0 . 0 143 11. 94 11.86 11. 95 0. 08 0 . 0 144 9.65 9.71 10.02 0. 0 0 .01 158 9.75 9.66 9. 99 0. 14 0 . 0 ... 179 9.18 9.15 9.48 0. 08 0 . 0 164 11.24 11.37 11.26 0. 0 0.12 194 10 . 94 11.00 11.08 0. 0 0 . 04 198 10 .82 10.59 10 .78 0.25 0.0 199 10.69 10.59 10.70 0. 12 0 . 0 205 11.06 0 . 0 11.09 0.0 0 . 0 208 9.39 9.23 9.44 0.19 0.0 235 9.83 9.74 10.03 0.13 0 . 0 251 8.88 8.85 9.15 0. 07 0 . 0 265 10.87 10.71 10.94 0.20 0 . 0 278 10.34 10.23 10 .54 0.16 0.0 281 9.30 9.25 9.62 0.10 0.0 . 283 8.65 8.62 9. 08 0.11 0 . 0 285 10 .81 10.81 10 . 92 0.02 0 . 0 288 11.75 11.71 11.75 0.04 0 . 0 291 8.15 8.10 8.61 0.12 0.0 ...296 9.26 9.10 9.58 0.23 0.0 318 8.29 8.29 8.74 0. 07 0.0 323 11.02 10 .95 11.05 0. 08 0 . 0 330 10 . 94 10 .87 11. 03 0.09 0.0 . 347 10.49 0.0 0.0 0. 0 0.0 353 10.14 10.18 10.43 0. 0 0 .00 354 9.88 9. 94 10.15 0. 0 0 . 02 357 11.23 11.15 11 .26 0.10 0 . 0 . 359 9.33 9.79 10.15 0.09 0 . 0 364 11.82 11.85 11.82 0.0 0.03 368 11.05 11.05 11.16 0.02 0.0 375 8.88 8.83 9.35 0.12 0.0 376 10.46 10 .44 10 .68 0.05 0.0 386 10.24 10 .25 10.59 0.04 0 . 0 387 8.64 8.57 9.11 0.15 0 . 0 392 11.19 11.24 11.32 0. 0 0.04 393 11.50 11.49 11.63 0.02 0 . 0 394 11.06 11.05 11.20 0.03 0 . 0 397 10.11 10.11 10.41 0.04 0 . 0 404 10.00 9.96 10 .26 0.08 0 . 0 408 10.81 10.76 10.93 0.07 0 . 0 411 9.78 9.79 10.11 0.04 0.0 417 10.80 10 .78 11.06 0. 06 0 . 0 420 ' 10.73 10.70 10.96 0. 07 0 . 0 422 10.52 10.31 10 .20 0.19 . 0 .,.0. _ 127 Table 29 (c o n tin u e d ) STAR MAG A MAG B MAG C TIO CN 425 7.73 7 177 7 . 95 0.0 0.01 428 9.43 9.37 9.54 0.08 0 . 0 434 11.21 11.03 10.94 0.17 0 . 0 459 9.09 9.11 9.27 0.0 0 .01 '468 9. 37 9.31 9.58 0 .10 0.0 469 7.52 7.46 7.68 0 .09 0 . 0 473 10 .16 10 .14 10.43 0.06 0 . 0 476 9.78 9.76 10.16 0.. 08 0 . 0 479 10 .07 10.14 10 .52 0 . 0 0.01 .... 484 11.37 11.42 11.86 0.01 0.0 501 9 . 94 9.93 10.29 0 . 07 0.0 503 10.89 10.98 11.27 0 . 0 0.04 511 9.47 9.36 9.80 0.18 0.0 519 11.26 11.25 11.37 0 .02 0.0 521 11 . 98 12.01 12.20 0 .00 0.0 555 10 .74 10.61 10.89 0.17 0.0 564 10.60 10.56 10.93 0.09 0 . 0 .. 565 . 10.21 10.24 10.43 0.0 0.00 566 9.74 9.54 10.04 0.28 0.0 574 10 .84 10.89 11.23 0.00 0 . 0 575 10 .26 10 .23 10.57 0 . 08 0 . 0 603 7 .89 7.78 8.21 0.17 0 . 0 605 10 .68 10.59 10.90 0.14 0 . 0 901 9.78 9.71 10.14 0.13 0 . 0 902 8.92 8.88 9.55 0.14 0 . 0 ... 903 . ... 8.0 0 7.93 8.35 0.14 0.0 128 Table 30: NGC 6752, Photographic Survey-System Magnitudes and Indices. STAR MAG A MAG B MAG C TIO CN 001 10.25 10.30 10.73 0 . 01 0.0 002 10.59 10.59 11.19 0 . 03 0.0 . 003 9.72 9.76 10.23 0 .02 0 . 0 008 9.79 9.75 10 .20 0 . 05 0 . 0 009 8. 99 9. 09 9.99 0 . 0 0. 09 010 11.05 11.00 11 .59 0 .19 0.0 on 10.60 10.60 11 . 05 0 .06 0 . 0 012 8.87 8. 95 9.29 0 . 0 0.03 016 8.95 8.33 8.75 0 . 18 0.0 018 8.63 8 . 68 9 .09 0.00 0 . 0 019 ' 11.31 11.26 11.59 0.09 0 . 0 029 9.67 9.79 10 .25 0 . 0 0 . 09 030 10.28 10 .93 10 .85 0 . 0 0.07 031 8.90 8.99 8.58 0 . 0 0 .01 033 9.85 "" 0.0 11.98 0 . 0 0 . 0 039 10.77 10.70 11.06 0 .12 0.0 035 10.39 10.19 10.99 0 .19 0.0' 036 9.35 9.51 9.79 o.o- 0.10 092 9.23 ' 9.36'" "9.59 0 . 0 0.09 093 10 .20 10.30 10 .91 0 . 0 0 .07 099 9.25 9.27 9.62 0 .03 0.0 095 9. 25 9.31 9.62 0 . 0 0.01 096 11.31' 11. 29 11.32 0 . 08 0 . 0 098 11.21 11.29 11.12 0 . 0 0.09 055 10.26 10.32 10.99 0 . 0 0.03 058 10.86 10.90 11.21 0 .00 0 . 0 U 5 9 8. 98 ' 8.99 8.63 0.0/' 0.0 ' 060 10 .78 10.73 11.00 0.09 0.0 061 9.30 9.33 9.78 0 . 0 0 .02 063 11.21 10 . 95 11 .26 0 .31 0 . 0 (J 6 8 9.90 ' ' 9. 91 "'10 .22 U . U 3 0 . U 069 11.93 11.30 11. 91 0.23 0.0 070 10.68 10.61 10.72 0 . 03 0.0 0 77 10.89 10 . 90 11.22 0 . 0 0.02 U88 ' 8.51 8. 9/ " 0 . 08 '"0.0"' 092 11.11 11.10 11.56 0.07 0.0 109 10. 91 10.86 11.37 0.19 0.0 105 10.02 9. 98 10.51' 0 .12 0.0 H i 10 .22 10 .23 " 1U . /a U . U8 ' u. u 190 10.81 10.79 11.19 0 . 08 0.0 159 11.99 11.39 11.57 0 . 18 0.0 160 9.82 9.72 10.10 0 .16 0 . 0 21U iO'.'yi... ’ "1U . / 6 11 . U 9 U . 2U u. u 212 9. 33 9.91 0 . 0 0 . 0 0 . 0 238 9. 15 9.23 9.69 0 . 0 0.01 251 8. 78 8.86 9.25 0 . 0 0 .02 2 / 5 8 . y9 9. 02 '“ 9.9U U . 0 U . U 2 276 9.67 9.73 10.06 0 . 0 0.01 281 10.59 10.60 10.85 0 . 02 0.0 289 9.19 9.38 9.59 0 . 0 0 , .18. 129 Table 30 (continued) STAR MAG A MAG B MAG C TIO CN 301 10 .86 10 .83 11.16 0 . 07 0.0 302 11.37 11.31 11.66 0.11 0.0 308 11.20 11. 08 11 .37 0 .16 0 . 0 319 10 .85 10.88 11.23 0 .02 0.0 323 9.13 0.0 9.66 0 . 0 0.0 324 10 .53 10 .56 10 . 92 0 . 02 0 . 0 327 11.67 11.50 11.86 0 .23 0 . 0 336 10.29 10.13 10.56 0.22 0.0 901 10.36 10 .33 10.83 0 .10 0 . 0 902 8.38 8.30 8. 98 0.19 0 . 0 903 10.62 10.58 10 . 97 0.10 0 . 0 904 11.62 11.43 11.71 0.23 0.0 905 8.90 8.89 9.76 0.14 0 . 0 906 10.10 9.99 10.51 0 .18 0 . 0 907 10.79 10 . ?2 11. 08 0.13 0.0 908 9.46 9.34 9. 94 0.20 0 . 0 909 9.44 9.38 10.01 0 .16 0 . 0 910 9.49 9.56 9.81 0 . 0 0 .03 J Y l sTTI 870? §739 0712 (TTq gur 2: i/N iga or 7 u. i ad N ndi otted e t t lo p s e ic d in CN and TiO Tuc. 47 r fo diagram TiO/CN 26: re u ig F o o .40 0.20 0.00 -0.20 -0.40 s mB. s rsu e v V 7 TUC 47 00 R B MRG 'V.2,, o d * ■'/do*- ■*%> & * % 9 ‘HI ;V1' 7 . 00 iue 7 TiO/CNFigure 27: TiO and diagram CN versus M5. for plotted indices o o o \j r f\J _ a o a CD o o a o o rr TiO rr 0 3. 00 V C> OU - - -f*V • - - • r — * 11 MflG . 00 O50L3 B OIOXO ~r“ 10 oo 3.00 3.00 131 M12 a Z.IOS'WO p j o \ o a o c a O -fS------ IZOGSO a p.j CJ U3 o 13.00 12.00 11.00 10.00 o'. 00 o’. 0 MAG B Figure 28: TiO/CN diagram for M12. TiO and CN indices plotted versus iue 9 TiO/CNFigure 29: diagram M92. for TiO and versus CN plotted indices O 13.00 .60 0.-40 0.20 0.00' 0.20 0.40 mB’ 12 M92 . 00 11.00 11.00 A B MAG 10 . 00 9.00 ~ 3 . 00 133 gur 3: i/N iga G 69. i ad N ndi d e t t o l p s e ic d in CN and TiO 6397. NGC r o f diagram TiO/CN 30: re u ig F O 20 1.0 00 9.00 10.00 11.00 12.00 .60 0.40 0.20 0.00 0.20 0.40 s mB. s rsu e v •!> G 63-97 NGC V * ' ' * V s s /?*• 'b •b ■ <*> v t, ,7 —y!r b -b ■b v — '•> f G B MflG % ■!> ■% 2-76 ■b <*> ,. 'b 00 135 NGC 6752 o a* CD r \i 2JS1<> o 360 0 O o CD O •'co 0^0 O o .o O O _ 0 - CD O O ru o o «- 7080 coo 3360 630 ZT o CD CCD 12. 00 11.00 ib. 00 9. 00 a. oo GO MRG B Figure 31: TiO/CN diagram for NGC 6752. TiO and CN indices plotted v e rsu s mg. 136 iris-magnitude relationships but that would require extensive observation of the faint stars which are the most difficult to observe. Another systematic effect, for example in NGC 6397, causes the mean TiO/CN index to differ from zero in clusters with a very small number of photoelectrically observed stars. The resulting systematic errors in the calibrations of the photometry exaggerate the sizes of TiO or CN depressions and are easily allowed for by defining corrected TiO or CN indices with respect to the mean TiO or CN index at the mg of that star. Stars with intrinsicaly strong TiO or CN depressions will still 0 be visible and better values are determined for the sizes of the depressions. I have examined the random errors by comparing the photographic and photoelectric indices, cluster by cluster, in Table 31. The photographic indices were corrected for systematic errors as described above and I define the quantity A as: A = ( Z (CN.* - CN.)) / N (11) isj ★ 1 1 where CN^ is the photoelectric CN index for star i, CN^ is the photographic CN index for star i, N is the number of stars . The quantity A is used to determine how well the photographic and photoelectric indices compare. For this purpose all TiO indices were converted to negative CN indices and used in equaion 11. This conversion is derived by adding equations 1 and 2 to obtain CN = -TiO + 0.13mA - 0.149mB + 0.019mc (12) For the present purposes I may set CN = -TiO (13) Table 31 Comparison of Photoelectric and Photographic Survey-System Indices. Units of Indices are 0.01 Magnitudes. Cluster Star TiO CN PE PG PE PG M5 1055 5 4 1058 5 2 1061 1 5 1067 17 6 1068 3 10 2061 0 15 4006 8 0 4059 0 1 A = 1 + M12 11001 10 7 11002 5 11 11016 3 4 12042 6 4 41024 1 1 A = -4 ; M92 3065 5 5 4010 15 2 4040 9 1 5045 0 2 6018 3 2 7010 6 3 7018 0 8 A = 3 ± NGC 6397 99 4 6 144 4 10 251 7 2 425 7 10 428 2 1 469 0 0 479 13 10 603 0 8 A = -6 : NGC 6752 9 5 10 16 22 12 31 3 7 36 10 16 59 1 1 138 T able 31 (c o n tin u e d ) Cluster Star TiO CN PE PG PE PG NGC 6728 68 3 3 911 6 2 A = -3 + 7 139 to sufficient accuracy, since m^ « mg for any star. Thus a single A can be defined for TiO and CN indices for each cluster. The values of A in Table 31 are all small and indicate reasonable agreement between the photoelectric and photographic indices after the removal of systematic errors. The standard deviations for A in each cluster are also given in Table 31. These standard deviatons reflect random errors in the TiO/CN indices which arise from two main sources: ( 1 ) the photoelectric photometry for the faint stars is based in some cases on as few as 300 to 400 counts and the photon statistics associated with these numbers imply photometric errors of 0.05 magnitudes; and (2) There are photometric errors of 0.05 to 0.09 magnitudes in the photographic photometry of as discussed previously. The standard deviations fo rA are reasonable considering the quality of the photometry. In fact the values are probably underestimated somewhat since the sample of stars in each cluster is small and the photographic observations were f it to the photoelectric photometry in the iri s-magni tude relationships. In each of the TiO/CN diagrams I have defined a _+ 0.09 magnitude band to represent the standard deviation expected in the indices. Systematic errors can also be seen in some of the survey-system color-magnitude diagrams shown in Figures 32 to 37 which were created from the magnitudes in Tables 25 to 30. The color mg - mg and the magnitude mg were used in these diagrams. There is a definite skewing of the colors below mg = 12.0 and 11.8 in the diagrams of M5 and M12 respectively. This is the same systematic error discussed previously in connection with the TiO/CN diagrams. The result is that only those stars which are brighter than the magnitude lim its given in Table 24 140 47 TUC o o r~ a ?Al* o ,WM v • .■L S o o t- >-Al -/*q o o CD »00 T>- d C_) /Od?' • * :«i5 CE q 200ft.- -V >137 ( 5r< *, >w? 11 C \j_ T^r i GO •0. 50 - 0.20 0 . 20 0.5 0 1 , 00 B - C Figure 32: Survey-system color-magnitude diagram for 47 Tuc. nu is plotted versus the mB - nu color. Filled circles are converted 8 -color photoelectric observations and filled squares are photoelectric survey-system observations. 141 M5 o o CO o o CD o c.j C_) ■9 LDa c r. 'i> 5 0 1 3 * st. o o fVI_ V 4-* B 'MJvs. -9l o m o m . 1 . CIO - 0 . 60 •0 . 20 0 . 2 0 0. 60 ? . 0 0 B - C Figure 33: Survey-system color-magnitude diagram for M5. mc is plotted versus the m„ - m« color. Filled squares are photoelectric survey-system observations. gur 3: vysse ormagniude darm for M2 m is mc M12. r o f diagram e d itu n g a r-m lo o c rvey-system u S 34: re u ig F o MAG C . m o -1 12.00 11.00 10.00 9.00 8.00 . 00 ur s em observatons. s n tio a v r e s b o m te s -sy y e rv su c i r t c e l e o t o h p otted verus he ng m color. quae are a ares u sq d e l l i F . r o l o c m~ - nig e th s rsu e v d e t t lo p -0. 60 -0. M 1 2 * •S *-& V / •% v v>'/ * . m * * „ 'VtV, 0. 6CJ •Jit, ;-v , •’• -• ’1< gur 5 Sur y-yse ormagniude darm f M2 m is i m^ M92. r fo diagram e d itu n g a r-m lo o c stem -sy ey rv u S 35: re u ig F CJ CD CD CD MRG o O (\J_ o CD CD . o O cn o CD o O cn. • .GO G . -•1 sus t B m col Filled s rs are ares u sq . s n d tio e a l v l r i e s F b o . r m lo o ste c -sy y mc e rv - su mB e c th i r t c s e u l rs e e o v t o h d p e t t o l p - M92 0 . •V 60 v \ ' d l I'f llO ■'o * j * *j> m ❖" • 0 - C - B . . 20 y- ,y ryj-l 0.20 0.60 0 0 . ? 143 gur 3: ve s tm col - t iga or G 69. nu NGC 6397. r fo diagram e d itu n g a r-m lo o c stem -sy ey rv u S 36: re u ig F MRG C 10 -0 O f.0 .0 .0 l'.OO 0.60 0.20 -fl.20 - 0. GO -1.00 12.00 11.00 10.00 9.00 • 6.00 1.00 ur s t i . s n tio a v r e s b o m ste -sy y e rv su c i r t c e l e o t o h p s plotted verus he B m col Filled s rs re a ares u sq d e l l i F . r lo o c mc - mB e th s rsu e v d e t t o l p is N G 6C' 3 97 '"V ^ "I ~ -" j O ^ •» i^i “ 9 '-HS - C - B o 144 145 NGC '6752 ...... o o r~ o o CO ■V o o ‘icn.v o c n LJ '& B ld 0 * ° ' V c , a c r io .1■t , «j» +l>2b ‘to** ■y ■# W' ra o .T. O , •* ^ •> •V o o C\J-_ -l . 00 • 0 . 60 ■0 . 20 0 . 20 0 . 60 I . 00 B - r Figure 37: Survey-system color-magnitude diagram for NGC 6752. m^ is plotted versus the mg - mc color. Filled squares are photoelectric survey-system observations. / 146 for M5, M12 and M92 have reasonably accurate magnitudes. There are no large skewings visible in the color-magnitude diagrams for NGC 6397 and NGC 6752 although their iris-magnitude relationships were extrapolated to stars fainter than any of the photoelectric standards. 4 ANALYSIS The method used to extract identifications of C and M stars from the survey-system photometry for each clu ster is discussed in section 4.1. Conclusions as to the usefulness of the survey system as a tool for discovering C and M stars are presented in section 4.2. 4.1 DETECTION OF C AND M STARS The TiO and CN indices given in Tables 26 to 30 have been plotted versus mg in a single diagram for each clu ster (Figures 26 to 31). The advantage of th is type of diagram is that systematic errors in the photographic photometry and the effect of these errors on the TiO and CN indices are easy to see as described in section 3.4. In addition, survey-system color-magnitude diagrams have been presented for each cluster in Figures 32 to 37. Stars with conspiciously large TiO or CN indices are labeled in Figures 26 to 37. The survey system can also be used to distinguish C and M stars from stars of other spectral types on the basis of data in only two filters, simply by comparing the brightness in filter A to the 147 148 brightness in filte r B for each star. Such comparisons are presented in Figures 38 to 62 for the eight clusters. Some of these A versus B plots use the raw ir is readings, while some use the readings corrected for cathode sensitivity variations. In the cases of clusters in-which the photographic photometry was calibrated photoelectrically, the axes are given both in terms of in corrected iris readings and in terms of magni tudes. The majority of each cluster's stars define diagonal bands in the cluster's A versus B diagram both before and after the corrections for variations in cathode s e n sitiv ity . These bands represent the average relationships between brightness in filters A and B for the stars of different luminosity in each cluster. Stars with stronger than average CM (for the cluster) fall to the left of the diagonal band since they are fainter in filter B than an average cluster star with the same brightness in filter A. Conversely, stars with stronger than average TiO fall below the band since they are fain ter in f il t e r A than an average star with the same brightness at filter B. Therefore these diagrams are a useful tool for revealing C and M stars in the clusters. The raw iris photometry can be used for this purpose provided that the images in both f ilte r s were located at the same spots on the photocathode. If this requirement is met then the variation in photocathode sensitivity affects each star's image in both filters by the same amount and sh ifts a sta r's position parallel to the diagonal band in its raw iris reading A versus B diagram. Since the shift is parallel to the diagonal band and not across it, the width of the band 47 TUC RAW IR I5 E 5 FROM ONE PLATE IN EACH f IL T E R Q Q O. r- o o O - co .C.' o o QQ. or?’-- , LTJ wT-’ X o DD 0> COq , m »,■ CD % O ■W mO. o o ra 0,00 30.00 >40.00 50.00 6 0 . 0 fJ I R I 5 B x l Q 1 Figure 38: A versus B diagram for 47 Tuc. Raw iris readings from the first plate in each of filters A and B are plotted. Plates cover the central 12 arcmin field of the cluster. 150 47 TUC RAW IRISES FROM □N E PLATE IN EACH F I LTFR a a r- o o a . . t o CD CD 'A* O a . ,_ _ ld X o ^ a zQ 'I .i.O tDci. ■— i J CL F? ° I cnQ-i I a a Av>. 0 . 4. •'O' — 1 ?0 . QO 3^.00 4 0. 00 5 0. U0 3 0 . 00 J. 0 0 I R I S 8 * 1 U 1 Figure 39: A versus B diagram for 47 Tuc. Raw iris readings from the second plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 151 47 TUC AVERAGED RAN IRISES FROM TNG PLATES IN EACH Q O FILTER o . r~ a o a _ oc & r, o o O a - t_, ui X 'b 0 f ^ >5 O LD q _ S'I*' .— i CC V o o o _ m Ay .fr\ o O o _ .. CM. T dO.OO 30.00 40.00 50.00 60.00 70. 00 I R I S B * 1 0 1 Figure 40: A versus B diagram for 47 Tuc. Averaged raw iris readings from the plates in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 152 47 TUC CORRECTED IRISES FROM SINGLE PLATES IN EACH a a FILTER o _ I— a <*t a Al J7V, Tt- end. i— i.t CO 4- * a o o. (n C> ft. O ■7> 9. ^0.00 30.00 4 0.00 50. 00 60. 00 70. 00 IRIS B * 1 0 ' Figure 41: A versus B diagram for 47 Tuc. Corrected iris readings from the first plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 153 47 TUC CORRECTED IR I5 E 5 FROM SINGLE PLATES IN EACH Q O FILTER o_, r~ o Q o _ CO <>vi OVf? c-vz a □ c -i __,ir> ; •yp/ooj X 0 (0'? , 01(7' V '%:■ O/floa cy. ovv n , 01 ° C7 OOJf to a _ .—, rr //eA 'S t.^ CO <•>. ^ 3S*>^- a ! .wJf>V O ! OJo«T Vr' cn°-i i a a o 00 30. 00 40. 00 ~ 5 0 .00 GO . 00 / o . no IR IS B x i a 1 Figure 42: A versus B diagram for 47 Tuc. Corrected iris readings from the second plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 154 47 TUC AVERAGED CORRECTED IRISES FROM TWO PLATE-5 O Q IN EACH FILTER CD_, r~ o — Oo MS c o yToAis < E » A < * / OlOi3 □ a . , LT> X CO O -L_5» i—i =r a z c-H, ■V o o o _ cn *' o o o lu II 10 B o . I _ 1 _ r u . %D.OO 30.00 40.00 5 0 . 00 GO. CIO 70. 00 IR IS B X 1 0 l Figure 43: A versus B diagram for 47 Tuc. Averaged corrected iris readings from the plates in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. The survey-system M spectral type calibration is shown. 155 gj ' CEN RAW IRIS FROM fltfC PLATE IN EACH FILTER Q O o r\j. rr CD o o rr. rr CD 0 — o Q(I3. 1 rr .•v r* X rV> CD ‘z‘ CE CD CD cnoo_ , , ,y&. •—irr CO > '' M CD 2 9 O 5 '* «■W^rr. 4 ,£.7 O CD. LO » <*v «.,.»^ O O CD CU_------!------^ ----T^T1------HO. 00 520. C?0 500.00 4 00.00 4 50.00 4 4 0. OC IR IS B xio1 Figure 44: A versus B diagram for ai Cen. Raw iris readings from the first plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 156 co CEN RAN IRIS FROM DM£. PLATE IN EACH F I L. ER C2 CD O Cd. IT CD O Q IT —1 "‘-I' =r t*, ” c- & a o lD*‘. - cn | v-?T. ^ O ld-| -',1 ,__ , IT ^ ' JC' 07 X & ?5.5^25 o : CC0 ; 2'” O - ^,-D V-' O cn 5 \ ' . C CO co ' c-V;W' / « o — ir ] *. X CD O Q_, ud o o C\j_ja I______!______^40.00 520.00 500.00 480.00 4S0.00 4 40.00 IRIS B KiO1 Figure 45: A versus B diagram for . w Cen. Raw iris readings from the second plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 157 co CEN RAW IRIS FROM TWO PLATES IN EACH FILTER a CD CD c\j. •T CD O CD rr_ cr o 0 - CD OLC'- 1 rr x o , L l - c c ° n’k'- CD £ > 7 COcD_ — ,.t i I GC , o '1'-? o i a ; O ! v, a _ j LID i CD o o (\J. ~ r ^ 4 0 . 00 520.00 500.00 430.00 4 u 0.00 440.00 IRIS B x 1 0 ‘ Figure 46: A versus B diagram for co Cen. Averaged raw iris readings from the second plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 158 Mb RAW IR I5 E 5 FROM QNF PLATE IN EACH FILTER CD .O CD CD o _ r~- CD a CEE*o ( i l Q . ,—i tn ai o o o _ rr a o a cn. 40. 00 50. 00 SO. 00 7 0. 00 Figure 47: A versus B diagram for M5. Raw iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. 159 MS CORRECTED IR I5E 5 FROM SINGLE PLATES IN EACH FILTER Cj o Q_ O Q OQ- . CD — -$> < '4'- o Z06I r o _ ■ »^L"!C62 g 0 ^ ^ °°3 0 . Q 0 40. GO 5 0 . 00 Figure 48: A versus B diagram for M5. Corrected iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. Photoelectric standards are underlined. 160 M1Q RAW IRISES FROM ONE PLATE IN EACH FILTER o a o _ CD O a o _ r— o O Q j ' - tol X I a;0 '9z- o CD o •—LTi CO w * ro 1------'30. 0Q 40. GO 0 0 . 00 6 0 . Cl 0 70. 00 50 . 00 IRIS B x I 0 ‘ Figure 49: A versus B diagram for M10. Raw iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. 161 MID CORRECTED IRISES FROM SINGLE PLATES . IN EACH CD a FILTER o CD *«■ CD a CD_ o Q C . ,LO V t, LO 0 _ ,— I LTI CO ,£• -',r‘ * OjL c. <:im o o cn. 30. 00 40. GO 50. 00 □ 0 . Ci 0 70 . 00 JO . 00 I R I S B x ILL Figure 50: A versus B diagram for M10. Corrected iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. 162 M 1 C RAW IRISES FROM ONE PLATE IN EACH FILTER o a o . no o v - t a o _ r- r»J.'y^ o o a< & . <-C a r° a (P a I & %% ------LD I cn o ! * * *■ a I . I C j _ T A CD Q <*. CD. cn 30. 00 40. 00 , 50.00 60 . 00 70. 00 60. 0 0 IR IS B * 10‘ Figure 51: A versus B diagram for M12. Raw iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. 163 M 1 2 CORRECTED IRISES FROM Z i 0 5 Li SINGLE PLATES IN EACH CD a FILTER CD. co - 0"- CD O n o o z o. * CD r- ff.nz4 .i -O o o C_m UODX^' j < E ^ i M k crQ a ‘1/Z065 t.o d _ - LT > CD O -■CM. />. 'lO o _ cr i - CD Q mr iz /i 10 l mCD_ 3 0 . 00 4 0 . 00 ;o. oo 5 0 .0 0 70. 00 o 0 . 0 0 IRISH x 10 Figure 52: A versus B diagram for M12. Corrected iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. Photoelectric standards are underlined. 164 M92 RAW IRISES FROM ONE PLATE IN EACH F ILTER CD Q Q CO CD CD CD_ r- CD • CD QCD h I * Q CD CD_ rT t - I—I LD "j L az CD CD CD _ T Figure 53: A versus B diagram for M92. Raw iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. 165 M9 c.^ CORRECTED IRISES FROM SINGLE PLATES IN EACH o o FILTER CD. cc -O- CD Q Q. r-' '07£; o a ,•1.•*C'R O o . ^ A'1 -i ,__ CiD 0^306$ X E O O lOJO'V O. .cr _r< *.V?V''^0 Figure 54: A versus B diagram for M92. Corrected iris readings from the plate in each of filters A and B are plotted. Plates cover the central 18 arcmin diameter field of the cluster. Photoelectric standards are underlined. 166 MGCS397 RAW IRISES FROM ONE PLATE IN EACH rILT E R O Q °-» r- o o % o _ CD o o O o _ , . LD o o o _ r\j c?0 . 00 30. 00 40. 00 50. 00 60.00 70. 00 IR IS B X 1 o ] Figure 55: A versus B diagram for NGC 6397. Raw iris readings from the first plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 167 NGCG397 RAW IRISES FROM CM PLATE IN EACH F ! R Q O Q. r - o o a . LO Cj o OCj. , Ln ■9 a ro ° c o o . $ 'VL< ■—i T -j U*. CO "b O Q a « v O. m Cfr. c> O' o . r\j_ 0.00 30.00 40.00 6 0 . 00 7 0.00 IR IS B Figure 56: A versus B diagram for NGC 6397. Raw iris readings from the second plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 168 NGC6397 AVERAGED RAN IRISES FROM TNG PLATES IN EACH O O FILTER a . n- o o o . iO o o CDo . LD <<«> X O CE O CO O. ■3* CC o o o o_ m Q O CM ;‘0 00 30.00 40.00 50.00 60. 00 70. 00 IRIS B *10' Figure 57: A versus B diagram for NGC 6397. Averaged raw iris readings from the plates in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 169 NGC6 397 ...... CORRECTED IRISES FROM SINGLE PLATE IN EACH cn o FILTER cz>_, r~- a o i_j _ t o o o Q C j . __ , LT) X 56fx 't* cod. I, c c *$*> CD O I ❖ <■!> o'5! o ay CD. t. 'j . DO 3 0 . 00 4 0 . GO GO. GO o i l . GO VG . 00 IRIS B x 1 U! Figure 58: A versus B diagram for NGC 6397. Corrected iris readings from the first plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 170 NGC6397 CORRECTED I R I 5 E5 FROM SINGLE PLRTE IN EACH O o FILTER r - o Q O. to A j 0 2 9 b Q . O 1 % □ O. __ , LH X •5^ ” rjSf>b iS, /W~ a : ° ; CDo. ,—i =r az § - / ’ a ! O ; a-I r n -’O O CO a o (\J.T 20.00 30. 00 40.00 5 0 . 00 SO. 00 7 0 . 0 0 IRIS B H lO 1 Figure 59: A versus B diagram for NGC 6397. Corrected iris readings from the second plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 171 NGC 6 3 9 7 AVERAGED CORRECTED IRISES FROM TWO PLATES CD CD IN EACH FILTER CD. CD HLS* CD c- t-03 CD. — C O CD O 251^. CD -o- 0 0 _| ,_, LD X < E /w... _ o CO CD. i— , r r CO o o Od; o _ m r , _o< CD Q /i / 1 JO mc 9> 7 I _L J_ I ^0.00 30.00 4 0.00 b 0 . 0 0 00. 00 vp. rm IR IS B x 1 0 ' Figure 60: A versus B diagram for NGC 6397. Averaged corrected iris readings from the plates in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. Photoelectric standards are underlined. 172 NGC6752 RAN I RI 5 E5 FROM ONE PLATE IN EACH FILTER O Q o . e' er) CD o _ to CD CD o o - ,_ Ln X '’j? a :0o cn o_ ►—i J J ' ai i & CD CD in ,' '' CD _ CO Si O ra“1 0 . 00 30.00 40.00 50.00 60. 00 70. 00 I R I 5 B x l o 1 Figure 61: A versus B diagram for NGC 6752. Raw iris readings from the plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. 173 NGC675D CORRECTED IRISES FROM SINGLE PLATE IN EACH C3 O FILTER n* —N o o o . CD • Oo 1/jo .vi^oa. O O a Oo_| .., in r-O"* I X s 3" ^,90 5? CEO o CO cl i—,rr CO o o o m 7cA.? i 4 ' 4 1 1 1 1 m 10 i B — r_ !\i,' T n. oo 30. 00 iio. on L'; r'i 60. 00 7 0. 00 IRIS B *. I o' Figure 62: A versus B diagram for NGC 6752. Corrected iris readings from the plate in each of filters A and B are plotted. Plates cover the central 12 arcmin diameter field of the cluster. Photoelectric standards are underlined. 174 is not increased, as a comparison of Figures 40 and 43 for 47 Tuc will show. Therefore the raw iris readings can be used to reveal C or H stars. I now consider the evidence for the presence of C and M stars in each of the clusters observed. 4.1.1 47 Tuc As noted in section 3.1.2, 47 Tuc is known to contain a number of late M type stars. This is quite easily seen in the TiO/CN diagram presented in Figure 26 for the central 12 arcmin diameter field of 47 Tuc covered by my plates. It should be noted that there is a systematic skewing of the band in the diagram because of residual errors in the calibration of the photographic photometry (see section 3.5). Indices which are corrected for the skewing in the TIO/CN diagram are given Table 32. Survey-system M spectral types, determined from the TiO depressions using the calibration in Table 5, are also listed in Table 32 along with spectral types from other sources. The potential mi scl assification by the survey-system photographic photometry is defined by the _+ 0.09 magnitude width of the band in the TiO/CN diagram which tran slates into +_ 1 spectral subtype at M2. Therefore some stars earlier than Ml.5 may be mi sclassified as late as M2. One such star, Rl, appears to have a moderate TiO depression athough its spectral type is B 8 III (Feast and Thackeray 1960). This star fa lls far 175 Table 32: Results of Analysis for the Globular Clusters (unit = 0.01 mag. in TiO and CN indices). Cluster Star TiO CN Survey 8 -color Slit i PE PG PE PG SpType SpType SpType Source 47 Tuc VI 16 M3 M4-5 GF V2 25 M3.5 M7.5 M4: GF V4 33 50 M4.5 V6 7 M2 M2 MO-1 FT V8 12 M2.5 M2-3 FT A1 26 M3.5 A2 34 M4 M4 TLE A4 6 M2 A6 36 M4 A9 9 M2 A18 22 M3.5 A19 14 M2.5 R1 14 B8 FT R2 3 Ml.5 K3 FT R3 5 Ml.5 K5-M0 TLE R8 1 1003 14 M2.5 1008 15 M2.5 1009 9 M2 1013 52 M5 1014 14 M2.5 2006 10 M2.5 M3-4 TLE 2008 13 7 M2 115 12 309 10 384 10 Cen 7 x 61 x M 143 X M Table 32 (c o n tin u e d ) Cluster Star TiO CN Survey 8 -color Slit PE PG PE PG SpType ipType SpType Source CO Cen 5 X 29 21 X C 95.5 X 131 X M5 5023 17 1020 14 NGC6397 164 20 NGC 6752 16 22 12 M3 M3 TLE 902 13 908 14 36 10 16 42 16 284 24 ■k Sources: GF = Glass and Feast (1973), FT = Feast and Thackeray (1960), TLE = Lloyd Evans (1974, 1977). 177 to the blue side of the giant branch in the survey-system color-magnitude diagram for 47 Tuc (Figure 32) and the e ffe c t of its steep near-infrared continuum on equation 1 combines with the photometric errors in mA and mB is to produce a false TiO depression. Three stars are included in Table 32 because of their apparent strong CN. These stars, numbers 115, 309 and 384, lie above the band in the TiO/CN diagram. Stars 309 and 384 are asymptotic giant branch stars according to their colors and magnitudes in the B, V diagram (Chun and Freeman 1978) while star 115 lies on the giant branch in the same diagram. Mallia (1978) has obtained spectra of 309 and 384 and finds no evidence of the X 4215 % band of CN in 309. He does not comment on the presence or absence of that CN band in 384. The strong-CN status of these three stars is less certain than the detection of M stars and further photometric or spectroscopic study of them should be carried out to resolve their status. The A versus B diagrams are presented in Figures 38 to 43 for the stars on my plates of 47 Tuc. Two plates were obtained in each filter; Figure 38 uses the raw iris readings from the first set of plates while Figure 39 uses the raw iris readings for the same stars from the second se t. Figure 40 shows the average of the raw iris readings for each star from the two plates in each filter. Figures 41, 42 and 43 are equivalent to Figures 38, 39 and 40 but use the corrected iris readings. The axes of Figure 43 are also given in magnitudes on the basis of the calibration for 47 Tuc given in Table 24. 178 The most obvious characteristic of Figure 43 is the number of stars which fall to the right of the diagonal band. These are the M stars which were also revealed by the TiO/CN diagram discussed previously. I have transferred the M spectral type calibration for the survey system from Table 5 into Figure 43 where it appears as lines of equal spectral type and can be used to determine M spectral subtypes. As expected, stars of spectral type <_ Ml.5 fa ll along the diagonal band although a few of these stars have been c la ssifie d as late as M2 by others. The three tentative strong CN stars (numbers 115, 309 and 384) fall to the left of the diagonal band in figure 43, but since unweighted averages from the plates in filters A and B were used to produce the figure, it is important to examine the single-plate diagrams for consistency in such cases. All three stars fall toward the left edge of the diagonal bands in both Figures 41 and 42. Thus th eir strong CN indices do not arise from a large photometric error on one plate, and all three appear likely to be K giants with enhanced CN. 4.1.2 Omega Cen I was not able to calculate corrected iris readings for my plates of Cen since they all cover the same 12 arcmin diameter field in the clu ster center where only a few stars, at the edges of the plates, have B, V photometry (Woolley et a l . 1966). Furthermore I did not obtain 179 sufficent survey-system photoelectric photometry to be able to convert the iris readings to magnitudes. Therefore no TiO/CN or survey-system color-magnitude diagrams are presented for this cluster. The raw iris readings are presented in A versus B diagrams (Figures 44, 45 and 46) and C and M stars are discernable in these diagrams. Two of the stars noted in Figure 46, numbers 61 and 143, show very strong TiO in filter A indicating late M spectral types. One other star, number 7, falls slightly to the right of the diagonal band and may be of early M spectral type. Finer calibration of the figure is not presently possible since there is insufficient photoelectric survey-system, eight-color, and B,V or V,I photometry to bootstrap the survey-system M spectral type calibration into Figure 46, the averaged raw iris A versus B diagram, as was done for 47 Tuc. Several stars, numbers 5, 29 , 95.5 and 131 fall to the le f t of the diagonal band and may have strong CN depressions in filte r B. One of these, number 29, is the carbon star first discovered by Bond (1975). The status of the other three stars is not as certain because their positions in Figures 44 and 45, the single plate A versus B diagrams, are somewhat inconsistent. Star 131 falls to the left of the diagonal band in Figure 45 and to the right of i t in figure 44. The position of stars 5 and 95.5 are not completely consistent in those two figures while star 29 falls to the left in both. Noise in the photographic photometry is probably responsible for the inconsistencies, and the strong-CN status of stars 5, 95.5, and 131 in w Cen should be considered as tentative. 180 Although Figure 46 is not calibrated in magnitudes, the CN depression for star 29 (Bond's carbon star) appears very small, about > half as deep as the TiO depressions in stars 61 and 143. If these last two have spectral types of about M4 then they would have TiO depressions of about 0.5 magnitudes, and in comparison star 29 would have a 0.25 magnitude CN depression. This value is consistent with the one photoelectric survey-system observation of star 29 which found a CN depression of 0.21 magnitudes. This value is probably an underestimation because the extremely crowded field of star 29 makes accurate photoelectric photometry difficult and the background may f ill in the CN depression somewhat. Furthermore, the CN depression is small in comparison to the other C stars in « Cen which are not included in the field covered by my plates. They have been observed photoelectrically on the 8 -color system (Wing and Stock 1973) and th e ir 8 -color CN depressions at filter 4 correspond to survey-system CN indices of about 0.5 magnitudes. Star 5 has about the same color and luminosity as star 29 (Woolley et al., 1966), which lies to the red side of the giant branch as do the other C stars in ween. Stars 95.5 and 131 have no published magnitudes or colors. All the « Cen stars described above are liste d in Table 32. 181 4 .1 .3 M5 The photographic photometry for the central 18 arcmin diameter field of M5 is presented in a TiO/CN diagram in Figure 27, in A versus B plots in Figures 47 and 48, and in a survey-system color-magnitude diagram in Figure 33. Several stars are noted in the TiO/CN diagram. Two of these, stars 2061 and 2080, have been observed photoelectrically and their apparent CN depressions are not substantiated. The scatter in the TiO/CN diagram suggests that their positions in the diagram are probably the result of noise in the photographic photometry. The remaining tentative strong CN star is 1020, an upper giant branch star according to Arp's (1955) color-magnitude diagram. Star 5020 appears to have a TiO depression but has no published magnitudes or colors. Stars 1020 and 5020 are listed in Table 32. Zinn (1977) has estimated the strength of the X 4215 8 CN band for a number of stars in M5 and finds several with CN enhancement. However, his strong and weak CN stars are not differentiated in the TiO/CN diagram. I have observed one of these stars, number 4059, pho toel ec tri call y and the depression at filter B does not appear enhanced. These results suggest that the CN enhancement seen by Zinn is not sufficently strong to be detected by either photoelectric or photographic survey photometry. Pike (1978) has also noted several strong CN stars in M5 from photographic DDO photometry but his strong CN stars show no d ifferen tiatio n in the TiO/CN diagram and the CN enhancement in one is 182 not confirmed by Zinn's spectroscopic study. 4.1.4 M10 The raw and c o rre c te d ir is A versus B diagrams presented in Figures 49 and 50 for M10 are based on one plate in each f i l t e r of the central 18 arcmin diameter region. The overall scatter across the diagonal band in Figure 50 is moderate, but since no useable photoelectric photometry was obtained for the cluster, I cannot estimate the scatter in magnitudes. One sta r, number 1070, appears to have a moderate TiO depression but its B-V color is only 1.2 and its position in Arp's (1955) color-magnitude diagram suggests the apparent depression is due to noise in the photographic photometry. With the elimination of star 1070 there are no stars that fall further from the center of the diagonal band than expected from the scatter across the band. This is especially true at the faint end where the iris photometry is more sensitive to noise on the photographic plate. Therefore no C or M stars are indicated by the survey-system photographic photometry of this cluster. 183 4.1.5 M12 Only one plate was obtained in each filter for the central 18 arcmin field of M12 and the TiO/CN diagram for the cluster is presented in Figure 28. All the stars fall inside the _+ 0.09 magnitude band except for 21054 which appears to be a field star since it is well displaced from the giant branch in both the survey-system color magnitude diagram (Figure 34) and in Racine's (1975) B,V color-magnitude diagram. Since star 12065 has a B-V color of only 1.07 (Racine 1975) its apparent TiO depression is probably due to noise in the photographic photometry. The A versus B diagrams for M12 are presented in Figure 51 for raw iris readings and Figure 52 for corrected readings. The iris-magnitude relationship for M12 given in Table 24 was used to calibrate the axes of Figure 52 in magnitudes. 4.1.6 M92 The scatter in Figure 29, the TiO/CN diagram for the central 18 arcmin diameter field of M92, is well contained within the +_ 0.09 magnitude band. Only one star, number 13014, falls significantly below the band, but it is on the blue edge of the giant branch in the 184 survey-system color-magnitude diagram (Figure 35) and its position in that diagram makes the apparent TiO depression doubtful. 4.1.7 NGC 6397 Two plates were obtained in each filte r for NGC 6397, each plate covering the same 12 arcmin field of the clu ster center area. The TiO and CN indices for this cluster are presented in the cluster's TiO/CN diagram in Figure 30. Several stars fall well outside the +_ 0.09 magnitude band and of these, numbers 198, 296 and 566 appear to have significant TiO depressions. However, their positions in the B, V color-magnitude diagram of Woolley et a l . (1961) are not consistent with this conclusion since they all have B-V colors in the range 1.0 to 1.2. Their apparently strong TiO indices are probably due to noise in the photographic photometry. This conclusion is supported by examining the single-plate corrected iris reading A versus B diagrams in Figures 58 and 59. In Figure 59 stars 296 and 566 appear to have sig n ifican t TiO depression of filter A while 198 does not. The opposite situation is seen in Figure 58 with star 198 having an apparent TiO depression while stars 296 and 566 merge into the diagonal band. Since the magnitudes used to produce the TiO/CN diagram were calculated from the average corrected iris readings, the averaging of the iris readings seen in Figures 58 and 59 produces the apparent strong TiO depressions in these stars. 185 Star 164 appears to have a strong CN depression in the TiO/CN diagram for NGC 6397 but its positions in Figures 58 and 59 are not consistent and its apparent CN depression may be due to photometric errors. It does lie to the red of the giant branch in the survey-system color-magnitude diagram, consistent with its position in the B, V color-magnitude diagram (Woolley et a l. 1961). 4.1.8 NGC 6752 One star in NGC 6752 has had its moderately strong TiO depression in Figure 31, the TiO/CN diagram, verified photoel e c tric a lly . This is number 16, which is listed in Table 32 as having a photoelectric TiO depression of 0.22 magnitudes and is spectroscopicaly classified M3 (Lloyd Evans 1977). Cannon and Strobie (1973) call it a probable field star on the basis of its position in their B, V color-magnitude diagram, but its position in the survey-system color-magnitude diagram (Figure 37) is consistent with membership. Furthermore its position in the B, V diagram is very dependent on the amount of TiO absorption in the B and V filters. Several other sta rs, in addition to number 16, appear to have strong TiO and are noted in the TiO/CN figure. Stars 63 and 336 are asymptotic giant branch stars on the basis of Alciano's (1972) B, V photmetry and their apparently strong TiO is doubtful. The other stars, 902 and 908, have not been observed before. They lie on the blue side 186 of the survey-system color-magnitude diagram (Figure 37) and they are both among the more luminous stars in the diagram. Three stars appear to have significant CN depressions on the basis of their positions in the TiO/CN diagram. Of these, stars 42 and 284 are giant branch stars according to their positions in Alciano's B, V color-magnitude diagram (1972) while star 36 is cla ssifie d by Mallia (1977 ) as an asymptotic giant branch star. He did not detect the blue CN bands on his spectrogram but I have observed the star photoel ectrical ly and the photoelectric CN index is in qualitative agreement with the photographic value, both of which are liste d in Table 32. The strong-CN stat s of these stars is tentative and further observations are desirable. 4.1.9 SUMMARY OF DETECTIONS The analyses presented in sections 4.1.1 to 4.1.8 have identified C and M stars and a number of potential M and strong-CN stars. Table 32 lis ts these resu lts of the photographic survey-system photometry in a more concise manner. M spectral types are given in Table 32 for the stars showing TiO depressions. Several of these stars have not been identified previously as M stars, while others have no previously determined spectral types. Only a handful of tentative strong-CN stars have been found in the eight clusters. In section 5 I will combine my resu lts with the results of other observers to summarize the occurrence 187 of these stars in globular clusters. 4.2 APPRAISAL OF CAPABILITIES The analyses presented in section 4.1 show that the survey-system photographic photometry does reveal the presence of C and M stars in globular clusters if their TiO and CN depressions are large enough. In all the TiO/CN diagrams the scatter appears to be about +_ 0.09 magnitudes, which is consistent with the discussion of photometric errors in section 3.5. There are obvious cases where photometric errors have resulted in values for these indices that produce misclassification on the basis of the survey-system photometry alone, as was discussed in sections 4.1.1 to 4.1.8 for each cluster. Most mi scl assifi cations from TiO depressions can be eliminated on the basis of the stars' positions in their cluster's B, V color-magnitude diagram, if available. The analyses also show the advantage of obtaining two plates in each filte r since photometric errors on any one plate can often be detected by comparison with an independent set of values from another plate in the same filte r. It is also apparent that the inclusion of filter C in the survey-system doubled the observing time spent on each cluster. This doubling is due to the dropoff of the sensitivity of the S-l image tube and is therefore an insturmental effect. As described in sections 2.2 and 3.5, filter C was included in the survey-system to remove the effects of continuum slope on the TiO and CN indices and to produce a 188 color index when combined with eith er f ilte r A or B. The color index can then be combined in a color-magnitude diagram with the C magnitude. The utility of the color-magnitude diagrams produced appears to be limited since the survey-system colors used in the color-magnitude diagrams are not very sensitive to spectral type and giant and asymptotic giant branch stars of different luminosities are not differentiated in the diagrams. These stars are much more easily distinguished in the B, V color-magnitude diagram since the B-V color shows a greater range with spectral type up to spectral type M. I made extensive use of the B, V photometry in section 4.1.1 to eliminate false TiO indices for stars in several colors which I could not have done using the survey-system color-magnitude diagrams. Omitting f i l t e r C from equations 1 and 2 would affect the TiO and CN index calculations minimally, by only +_ 0.04 magnitude errors in the TiO and CN indices for the bluest and reddest giant and asymptotic giant branch stars. This error is less than the scatter in the TiO/CN diagrams that arise from photometric errors in the photographic photometry and would have little impact on the determination of spectral subtypes for M stars. Therefore it appears filter C could be deleted from the survey-system if the information it provides can be obtained from others sources, such as B,V photometry. The errors thereby introduced in the TiO and CN indices are less than the photometric errors, and more importantly, a significant savings in observing time can be realized by not measuring filte r C. The analysis of <*> Cen in section 4.1.2 supports my conclusion in 189 section 4.1 th at the raw iris photometry can be used to detect C and M stars provided that the telescope is not shifted between exposures in filters A and B. Therefore interesting objects can be targeted for further study as soon as the iris photometry is done, before any further reduction of the photographic data is carried out. These conclusions and those from other sections indicate that the following observing techniques should be used to optimize the usefulness of the photographic material obtained with the survey-system f ilte r s : (1) The telescope should not be shifted between exposures on a given cluster. (2) At least two plates should be obtained through each filter. (3) Flat field plates should be obtained each night for later mapping of the photocathode sensitivity variation (see section 3.3.1). (4) An A versus B diagram should be produced as soon as possible from the raw iris readings for each cluster to target interesting objects for further study (see section 4.1.2 on wCen). (5) The raw iris photometry can be corrected to a great extent for photocathode sensitivity variations using the method described in section 3.3.1. 5. SUMMARY None of the tentative strong-CN stars listed in Table 32 can be classified as C stars on the basis of their survey-system CN indices. At best, they appear to be enhanced-CN K-type stars. This is also true for Bond's CH star in w Cen since its CN index is only 0.21 mag., which is less than half the depressions for the C stars in that cluster (see section 4.1.2). The result is clear; no "classic" C stars were found in any of the eight cluster fields studied although the survey system photometry would have easily revealed such stars. Another cluster, M22, contains at least two mild CH stars (McClure and Norris 1977; Hesser and Harris 1979) and has [Fe/H] = -1.86. No eight-color or survey system photometry has yet been obtained for these stars and I cannot compare their CN strengths to the other C stars and strong-CN stars I have observed. I mentioned in section 1 the possibility that CNO abundance variations in a globular cluster may be related to the overall m etallicity of the c lu ste r. However, th is does not appear to be the case since no carbon stars have been found in the metal-rich globulars, only in the metal-poor clusters wCen and M22. There is a greater range, on average, in CN strengths in the m etal-rich clusters than in the metal-poor clusters, but this effect may be due to the difficulty 190 191 in measuring CN variations in the metal-poor globular cluster stars which have very weak CN bands to s ta r t w ith. It may be th a t the processes that resu lt in the presence of C stars in some globulars may be quite different than the processes which produce the CN variations in the metal-rich globulars. In fact, it now appears that there is a range in CN strength among the main sequence stars in the prototype metal-rich globular 47 Tuc (Hesser and Bell 1980). This suggests that the CNO abundance variations seen among the 47 Tuc g ia n ts may be primordial. The occurrence of M stars in globular clusters shows a much better correlation with cluster metallicity. They are numerous in metal-rich globulars like 47 Tuc and scarce in metal-poor globulars. This is fairly well understood as an effect of metallicity on atmospheric structure and is quite easily seen by the different positions of the giant branches in the bolometric magnitude-effective temperature plane for the different clusters. The giant branches in metal-rich globulars extend to cooler temperatures than do the giant branches in the metal-poor clusters. The metal-rich clusters therefore contain more cool giants which have strong TiO bands since the strength of TiO bands is very temperature sensitive. There are, however, several notable execeptions to the rule. Omega Cen, which is classified as a metal-poor globular from the shape and position of its giant branch in the color-magnitude plane, has several late-M stars which are well separated from the giant branch (which terminates at about K4). NGC 6397, another metal-poor globular, contains at least one and possibly several M stars. Thus there appear 192 to be other factors than overall cluster metallicity which determine the presence or absence of M type stars. The occurrence of C and M stars in globulars remains a complex problem and is dependent on a number of factors. Cluster metal lic ity and its e ffect on atmospheric structure is the dominant effect for the presence of M stars while there appears to be no one explanation for the CNO abundance variations indicated by the presence of C, M and strong-CN stars in some globulars. Much more work is needed before the evolution of globular clusters stars will be completely understood. LIST OF REFERENCES Alciano, G. 1972, Astron. Astrophys., 16, 220. ...... 1977, PASP, 83,491. Arp, H. C. 1955, A. J_., 60, 317. Baumert, J. H. 1972, Doctoral Dissertation, The Ohio State University. Bell, R. A., Dickens, R. J. & Gustafsson, B. 1975, Bull. AAS, 7, 535. Blanco, V. M. 1965 In Galactic Structure, eds Blaauw, A. & Schmidt, M. (University of Chicago Press, Chicago), p. 241. Blanco, M. F., Blanco, V. M. & McCarthy, M. F. 1978, Nature, 271, 638. Bond, H. E. 1975 Ajd. £. (Letters), 202, 147. Cannon, R. D. & Strobie, R. S. 1973, Mon. Not. R. astr. Soc., 162, 227. Carbon, D. F., Butler, D. & Nocar, J. L. 1977, In CNO Isotopes in Astrophysics, ed Androuze, J. (Dodrecht, Reidel), p. 33. Chun, M. S. & Freeman, K. C. 1978, A. J_., 83_, 376. Dickens, R. J. 1972, Mon. Not. R. astr. Soc., 159, 7P. Dickens, R. J., Feast, M. W. & Lloyd Evans, T. 1972, Mon. Not. R. astr. Soc., 159, 337. Feast, M. W. 1973, In _I.A.U. Colloquium No. 21, Variable Stars in Globular CTusters and Related Systems, ed Perme, J. D. (Dordrecht, Reidel). Feast, M. W. & Thackeray, A. D. 1960, Mon. Not. R. astr. Soc., 120, 463. Glass, I. S. & Feast, M. W. 1973, Mon. Not. R. astr. Soc., 163, 245. 193 LIST OF REFERENCES (C ontinued) Griffin, R. F. & Redman, R. 0. 1960, Mon. Not. R. astr. Soc., 120, 287. Harding, G. A. 1962, Observatory, 82, 295. Harris, W. E., Racine, R. & De Roux, J. 1975, Ap. J. Suppl., 31, 13. Hesser, J. E. 1978, A£. J_. (Letters) , 223, L117. Hesser, J. E., Hartwick, F. D. A. & McClure, R. D. 1977, Ap. J_. Suppl., 33, 471. Hesser, J. E. & Harris, G. L. H. 1979, Ap. J_., 234, 513. Keenan, P. C. 1963, In Basic Astronomical Data, eds Blaauw, A & Schmidt, M (University of Chicago Press, Chicago), p. 78. ------1973, Ann. Rev. Astron. Ap., 11, 29. Keenan, P. C. & Morgan, W. W. 1941, Aja. J_., 94, 501. Kron, G. E., White H. S. & Gascoigne, S. C. B. 1953, Ap. J., 118, 502. — “ Lloyd Evans, T. L. 1974, Mon. Not, jl. a str. Soc. , 167, 393. ...... 1977, ibid. 178, 345. Mallia, E. A. 1977, Astron. Astrophys., 60, 195. ...... 1978, ibid, 70, 115. McClure, R. D. & Osborn, W. 1974, A£. J. , 189, 495. McClure, R. D. & Norris, J. 1977, Ap. J_. (Letters) , 216, L101. Mould, J. R. & McElroy, D. B. 1978, A|k £., 221, 580. Mould, J. R., Stutman, D. & McElroy, D. B. 1979, Ap. J_., 228, 423. Norris, J. 1978, I.A.U. Symposium No. 80, The HR Diagram, ed Philip, A. & Hayes, U7 S. (Dordrecht, Reidel) p. 195. 194 LIST OF REFERENCES (C ontinued) Norris, J. & Zinn, R. 1977, Ap. J_., 215, 74. Norris, J. & Bessell, M. S. 1977, Ap. J_. (Letters) , 216, L191. Norris, J. & Cottrell, P. L. 1979, A^. J_. (Letters) , 229, L169. Norris, J. & Freeman, K. C. 1979, Aja. J_* (Letters), 207, LI 13. Osborn, W. 1971, Observatory, 91, 223. ------1973, Ap. j_., 186, 725. Peterson, C. J. & King, I. R. 1975, A,. J_., 80^, 427. Pike, C. D. 1977, Mon. Not. jl. astr. Soc. , 183, 101. Racine, R. 1973, A. £., 78^, 180. Sandage, A. R. & Walker, M. F. 1966, Aja. J_., 143, 313. Shakespeare, W. 1603, Hamlet (London, John Trundell). Sharpless, S. 1956, Aja. J_., 124, 342. ------1966, In _I_.A.U_. Symposium No. 24, Spectral Clasification and Multicolour Photometry, eds Loden, K., Loden, L. 0. & Sinnerstad, U. (London, Academic Press), p. 345. Stock, J. & Wing, R. F. 1972, Bull. AAS, 4, 324. Stock, J. & Wroblewski, H. 1972, Pub. Dept. Astr. Universidad de Chile, 2^, 59. White, N. M. & Wing, R. F. 1978, Ap. J_., 222, 209. Wing, R. F. 1967, Doctoral Dissertation, University of California, Berkeley. ------1971, In Proc. Conf. Late-Type Stars, ed. Lockwood, G. W. & Dyck, H. M. KPNO Contribution No. 554, p. 145. Wing, R. F. & Stock, J. 1973, A^. J_., 186, 979. Woolley, R. v. d. R., et a l. 1961, Roy. Qbs., Bull., No. 43. Woolley, R. v. d. R., et a l. 1966, Roy. Qbs. Anna!s, No. 2. 195 LIST OF REFERENCES (C ontinued) Yorka, S. & Wing, R. F. 1979, A. 84, 1010.