1971ApJ...163..121I single Treating light and periment atmosphere changed analysis. However, this study, with studies Martian the polarimetric et ward were 1966) interpreted. 80mb, are atmospheric no Rayleigh resolution surface polarization analyzed limit the THE @ © al. The For *Contribution Similarly, As This detectable Ground-based existence 1971. shortest its limit consistent American and AsTROPHYSICAL on still about Division 1965; several POLARIZATION free a or the pressure and main polarization mainly Rayleigh RAYLEIGH either The paper result on to failed albedo. atmosphere and observation the much because scattering surface, these parameter from varies the University the an of Kliore from 0.003 wavelengths polarization For haze. difficulty data of atmosphere fine times Carnegie atmosphere. in failed is assumption Astronomical upper of on with to estimate Geological No. scattering larger polarimetric 3200 the inversely data a For dust many this that take measurements the JouRNAL, have one of et report For 1738 of range at (Dollfus in a most to al. limit. in the Chicago. (Dollfus Institution SCATTERING then to work, basis were than must of in all model .Mercury, into the these of years, consider recently 1969). of Sciences, equal of Received as 4-7.5mb, 7000 data analyzing the (Morozhenko of scattering which as MEASUREMENTS wavelengths. the surfaces, Martian an surface The surface data describes 163:121-129, the of reexamined account Society rely polarization it All a planets' surface. and Division optically to in polarimetric have A. and the appears The layer estimates rights of present taken 0.001 197 ANDREW restricts on California which data made been the The if albedo. atmosphere. Washington, Focas Martian pressure 0 Focas I. an C0 been empirical the • occultation reserved. the power March of data the of of near Provided Thus INTRODUCTION thin, atmospheres. 2 aim inverse at ABSTRACT cited IN 1971 at is that the 1970). data Geological study Rayleigh there (O'Leary polarization For cited 1966; measurements the amount of the the 121 Institute P. 1969; ultraviolet maximum are Rayleigh-scattering 11; Earth's of THE data Printed January of one now 5-7mb Mars, surface For previous principal as INGERSOLL number is California formulae shortest the revised relation is consistent gives as These the by Pollack separating data evidence Mercury, Morozhenko needs (Dollfus OF 4-7.5 agrees evidence Sciences, in MARTIAN of atmosphere. study scatterers of the the and Earth's U.S.A. 1 elongation Technology, from an 1970 For pressure constituent. light errors are of best MARS wavelengths of NASA polarimetric Institute exists; a wavelengths relating mb improvement Rea 1967), light with free of the June was model Mars, generally with California fit 1961). of radio-occultation of scattered out Mars of best atmosphere are atmosphere, to Astrophysics parameters 1967), fine is an the to 24 that reflected are was 1970). AND of a the C02, ATMOSPHERE* but the and one polarization There these based fit corrected atmosphere measure This model Technology presented. haze occultation and data to is, believed Institute are Hale effect accepted, data the such and the with (Dollfus by for However, is MERCURY: by was and Mercury on yields considered by or and no data in Observatories, resulting the a of (Dollfus this have a assumption; of Data laboratory the need no in aerosol given which the revised previous factor a of These the yields data to an the of atmosphere on surface the Technology. value. permanent figure and and amount surface to been scattered System estimate problem. be Mercury previous at viewing planet's postulate present there an data (Kliore figures of 1961). in so down­ in Focas 200 about whose upper data mis­ 3 was the the ex­ the are in at of is of A a 1971ApJ...163..121I If cording Introduction, Values where If is The Thus a that the planet portion to beam, by depth electric the ment that may planet, perpendicular servation assumptions. form observers observations the tween such optical of of geometry the Coffeen (Gehrels, 122 and © simply the Light I Let the A The polarization wavelengths. the atmosphere J. surface atmosphere phase American geometric is, number the neglect that and if of of measurements s, intensity the are is this the p atmosphere. of observations 1rF depth and to vectors is at 1965). this respectively. surface from important; is planetary the m are Iu Coffeen, both at precise 0 taken the angle when equation light each the and polarization is fall the relationship are the all of total were relatively this Astronomical can the the degree to albedo average When small. of previous simplifications of and are can polarization, scattered Earth. value in wavelengths between one The to illumination the value the solar planet light a relation be intensity and the made albedos be Second, perpendicular (2) perfect that and be themselves refer intensities is made. this polarization The of plane First, A zero. of range flux of so large, neglected. scattered For Owings depends less of third, of studies which polarization consists is the the at is A to that at surface appears Mars and a diffuse at of Society the important. done, Mars, the only log of over in light 8 point a where phase and Sun the of the both ANDREW are = the m point the has scattering, II. major of 1964) are atmosphere oe are on the first-order and by 105°. of the planet from other a the These component and possible is and these attenuation reflector the METHOD = - = on interval to been 0. • Mars reasonable the relatively angle two a the 0 atmosphere the assumed on Mercury 7 Provided entire and b hold conclusions the and source comparison = observations the parallel The the Nevertheless, < are chemical is m full scattered the components, components: in planet assumptions IJ. IJ. and P. disk m 8, small, albedo log if Earth of which for a entire independent of facing OF divided disk, scattering, + -In. data and wavelength planet specified both INGERSOLL the < of powders is straightforward. Mercury to the on ANALYSIS by is determination A. of Iu to near 1.4 uncertainty assumed surface surface by and the and where be the planet, in the the is agree derived of the + by the o. Moon is be by . , were the the the linear; ratio the and possible. log maximum NASA incident physical one the basis wavelength vice Sun then are that plane in resolved F directly the are with surface Martian albedo may coverage, 0 plane b surface equation and surface, made to can the A. • verified from at of versa. wavelength. ; which The of the low albedo Astrophysics its obey in of the the vary be for of laboratory those place observations beam properties The One containing degree direction this scattering, out at and the geometric into elongation is and the treated same total vary most Specifying sky; denoted has interval, a a consistent (2) 8 with the of main of reasonable measures relation analysis. study; as atmospheric posteriori. published Rayleigh-scattering = components that the been may intensity the location of systematic for it with silicate 42.5°, As wavelength separately; Data passes of differences is polarization (Dollfus unilluminated of incident Mercury, albedo by the the stated still scattered respectively. errors at of found the of wavelength the the with the subscripts where System the a albedo powders. by limits the The Sun, in be surface. through IJ. Vol. number surface precise optical degree space. whose of of in Moon treat­ valid 1961; other to + these form solar fact one 8 the the ob­ the the (3) 163 be­ ac­ (2) (1) by on be I11 A is is 1971ApJ...163..121I know ofT empirical albedo a constants planet surface (6) is Equation tions These geometric eter combined where molecules atmosphere No where geometric involve the sufficient what wavelengths with No. A.(X)j given also © If The Since The X is and optical 1, rX American 4 the Loschmidt's (6) the the follows, reflects specified n 1971 o J.Lo 4 expressions pare A.(X value polarimetric • geometric geometric a (7) r can is And polarization and scattering albedo condition and albedo contribution varies (8) rX in albedo albedo expression the depth 0 give at ) 4 taken be the of and since the uncertainty is (7), and be it J.L Astronomical index a in m, expressed derived is as are atmosphere. point A. only independent A. of of phases terms albedo r, to number, -are albedos chosen b assumed from the x-4, o for at law POLARIZATION the data the are the of which replaced the - = data may the geometric singular from that this (J.Lo, refraction the from planet: of p the surface 1 for determined cosines data p.(X), of I from in refer [(3r/81r)(1r average a.l. rX refer p(X, be albedo to is J.L) Z point, Society that Pa data the interest the terms To in 4 defined equations - _ be is by • by is of integrated the = Thus mas to at given surface, the atmosphere p. fJ) 3F0r. to of valid find given albedo these position of 16J.L the of the 8 3r Pa(X) as a is range the 11' albedo of have a the Irvine vertical • the well by Ps in range at known. Pa, well single (1r surface as method Provided the by - ' is OF by conditions limb, angles = all this fitting is of (1), medium - follows: that note e.g., 8)(1 of been as three to as on completely MARS P- I p. the et wavelengths 8)(1 values of all the point coordinate, study Pa, (2), the give al. This but the the for component that - of planet wavelengths - _ of measured by equation uncertainty Pa free which + (1968). polarization. cos and constant least at 3F0r the disk, incidence the AND on are 16 the the (3). atmospheric 1 the cos (Irvine standard 2 parameters J.L the 8) p(X) whole (5), NASA specified fulfilled. singularity intensity Thus 2 squares. atmospheric must for COS 8) Each the MERCURY + and (8), disk for of with m 2 is . all bp,-m+l]. et degree due 8 and X the planet. be Astrophysics known, the and N in as and Mars 1 temperature determination al. Unfortunately, wavelengths at (J.Lo, by A. subtracted is contribution Values uncertainty of to conjunction rX4, reflection, geometric the 1968). a the is the light errors = of J.L), single Thus contribution integrable, this spectral m, p. polarization number single it of scattered in and However, Mercury of is means Data the one phase equation and off necessary respectively. observation. albedo X in free is depends b: with reflectivity and geometric before equations density System the needs made pressure, that and param­ 8. by to of value X equa­ at these p 0 The •. (2). • 123 (9) the the the the the (7) for the (8) (6) (5) (4) an on all In to of A 1971ApJ...163..121I fined both pendicular perpendicular and a.c. in the nal value necessary and quency disk The izer values. method reflection reflection within planetary be This, is the may was are of greater where geometric at length. which naert 124 slight, © The the The After each a Equation the quite was a.c. channel polarization both then (Karl operated American point analysis (Polaroid be the by in of plane 1941; represents the x-axis the output observations of wavelength On channel For than wavelength-dependent. sychronously of the m conjunction the direction and insensitive into outputs at must science that the Polaroid albedo, on Lambrecht allowed lower to is least the the of a second to phase Harris 90°. (9) of and the is the at the second the direction. Astronomical of polarization.) Corporation the the be other Moon, therefore observational to squares. the is introduced main equality the the p8 planet detector, However, laboratory were plane the parallel of (I two intensity ranges, of integrated in right-angle to 0 =- were 1961). Cassegrain J. distribution d.c. mirror with polarization hand, demodulated deflected terms the = Corporation), - which source disk. k simultaneously C mirrors 71" of Measurements is varies Iu) (3r/16~J-)(1 channel made In neglected 8-r/2 reference is equations to and then scattering, an In type f Society at C in of (A of by The r/2 of III. satisfied equation cos value (3r/16~J-)(1 the S-20 of ANDREW data over is a the general, the [cos the reflection, be then beam the in with 180° focus, the given uncertainty 1/;, HNP'B), directly METHOD d.c. z-axis of is and the polarimeter. of two photomultiplier of polarized where by California proceeds 0.5 • signal. in the (8- intensity proportional reflection determines rotation (6) a then the - component of k Provided be at range the the degree phase (12), off photoelectric use parameters recorded is k in < disk cos at and + the zero same ¢) and chosen proportional OF P. the if; the order through d.c. present k then of Thus two 2 cos is as INGERSOLL cos 8) < OBSERVATION y-axis, component, as to angle, in (7), as of a C beam of phase axis Institute the at material by channel 2 Thus, in + phase 1.0' values the before: a through obtain vary the 0) on the that ¢]kd¢ from polarization if to enables the function the equation phase b(CIJ.okiJ.k-l)-m+l analysis. of rX + an tube. the a determination the the Polaroid passed then the optimal polarimeter and 4 NASA the d.c. if the with -1 the reference CIJ.okiJ.k Cassegrain interference and to f(1 of incoming is signal one the One of dependence (i.e., total of a 1 The polarizations the resolved telescope, the range strip surface one proportional if; Technology. two-element k. of phase the through surface lets (8), Astrophysics In are chooses values - corresponds The aluminum). direction position of a.c. intensity, upper 1 was to chart fact, reference ~J- driven of the sufficient the the 2 which specify light )kdiJ.. angle component albedo, degree flat physically along amplified of filter axis contribution of in a of incident uncertainty equality the values recorder. rX on rotating was rX such k is cancel. at after to The was quartz and and 4 of a • present on of Data (Oriel the relative 4 the polarized to twice and I to and direction the canceled J. polarization wavelength built of a instrument with separately, a that the value disk reasonable +In, light. determine of at System full way telescope It therefore Polaroid m b depolar­ Optics), Vol. the the second by phases results is in to to of in and wave­ (Min­ cycle of The that per­ ( (11) (10) and also fre­ sig­ the the de­ the the 12 the 163 the by C k ) 1971ApJ...163..121I ditions many shown less ment scopic comparison of The longitude the erate 0.15 approximation, or planetary planet. 5 in made was 1970). U.T. position (p. low with ning sufficient standard several varied (Arabia) signal from fluctuations the negligible residual with system tions. (Appenzeller No. seconds. 0 © The The diameter The the 0.25 The Guiding Several , It albedo accuracy than p.) elevations near results 1, American of the north-south slopes. with between is this the sets 1970 data It 1971 to phase are from planet of observations were results Thus relative degrees of the was possible, polarization error correct appears at the the error 0.005 object Arabia accuracy scale system. polarization. the observations telescope the of of checks was of with planetary April (Belton calibrated was Martian 0.02 In normal in it angle center of d.c. observations this 1966). the was their was planetary of Astronomical 100-inch the determined was of addit; the sky at on the elevation the done used. signal north-south the the at in at that signal angle first along 18 region scanned the ultraviolet One limited were Mars, up for possible direction method data and of principle, long the POLARIZATION on of on present second First, was and em, with latitude diameter. this The night longest the in to Mars the in background scans 1969 This in Mount by telescope time the to Hunten made diameter. since and is probably wavelengths advance of (J and each 19 the disk mainly is an in Dollfus taken obtain purposes the seeing fairly by = was night Society to data. IV. illuminated are this were August was a setting, of from each this way the on image direction inclined to 40°; and the wavelengths moving follow fairly the instrumental by at channel Wilson. the less RESULTS tested The 1969) and make region never present on during typical of The was made the bright by by the scan less data 0300 and longitude The using their scans • during complete, observation, of Mount of typical 12 Arabia the integration using seeing. Provided off time OF degree to was average, data than aperture the by and the of measurements Focas the more was separately. and American The 1969 were of to limb several areas data 0.13 of planet OF the data stars coincided polarization. using MARS telescope planet about of Mars completely the radar experiment. 0330 of and 0.001 the made. Wilson. region 13. OBSERVATIONS as polarization Martian August of object, +10° than observation. at analyzed (1969) Dollfus have (east but comprise indicates by scan. it whose and albedo stars This plate polarization. 0.01 was different short 1969 hours 0.002 time has AND moved after data was the Ephemeris differences 0.007 of One with and been or the to The scanned for and 12 is at with NASA been intermediate with and located August data against wavelengths, polarization of (Pettengill of the west polarized Since the in consistent MERCURY by U.T. and position about that the 320°, then bright the through at observations extrapolated the the was the then oppositions. Focas appreciable correction A west a measured using refer any Astrophysics shortest limb) 13 direction the Martian circular mirrored This by on degree planet in electronic takes was photoelectrically 13, determined respectively. 0. a subtracts from regions, o at wavelength, 70 bright measured represent light moving error the to some are the for et with used method of 4" elevations of has the this a al. of as 0330 wavelengths. shown 24-inch was the aperture by the exact the in min- atmospheric of large polarization. was front The of 30° to polarization a the sky 1969; to taken ratio equipment been known was rotation Data east-west. two using Mercury whole. made. the Martian planet. 0 to from the establish polarizations of is about 1 observation close This = background in coordinates • bright surface. 0530 and considered To limited longitude, nights lunar of sky and Goldstein at measured results System 42.5° Figure about by spectro­ orienta­ Second, stars the a values agree­ region Then, so of 2", hours signal mod­ scan­ disk, good were Also con­ area The The was and and the are 125 the a.c. for the At 2" by of or 1. of 1971ApJ...163..121I ment between observations cinders Thus likely The where of that 1969 tremes are Dollfus based 126 © k The Recall FIG. observations American and normal choice July on in the to the and !.-Polarization of results and photometry surface m be favor that Table uncertainty uncertainty 31 Focas the rX significant k particles atmospheric better. and 4 = Astronomical of k taken values of = (1969). polarization 1 0.75 describes 0.7...... analyzing 1.4...... 1.0...... m August are (1.9 - ...J 0. 0 <( 0:: i= ~ 0 <( z f1. of * 1969 = Values 101- 12 whose of 14 Expressed is 0 Mars 2 61- 4 not of 81- 1.4 in in is ± 1, II 1- Arabia ~ .70 appropriate rX August the the m the VALUES conditions 0.2) 5 but appropriate the .4. X • by 4 1.6 ..:..~ Society the polarization (Leighton I (ALBE00)- ARABIA BRIGHT which standard determination of of and distribution in (OOLLFUS .60 Irvine at distribution a ANDREW X 1 m data 13 1.8 o-4 the slightly I OF albedo. CHOICES 10- at between (THIS REGIONS WAVENUMBER provide (pm)4. WAVELENGTH(p.m) • center et k=O.S rX prevailed 2.0 for 0330-0530 1 2.4 1.8 1.2 of 4 Provided a I al. 4 .50 I error except et * (JLm) WORK) FOCAS) TABLE Figure FOR the and smaller (1968). al. Gehrels 2.2 of of P. I OF of the 0.7 based 4 the 1969). MARS brightness Moon INGERSOLL albedos , k at brightness rX hours at 2.4 by best 1 Martian AND 1 Triangles and very 4 for value et the • (p.mr b the .40 I on k FOR The 2.6 ==0.75 al. 2.6 1.9 1.3 at = U.T. fit m I the 1.0 the time NASA large were VARIOUS (1964) (2.4 8 to disk constant 1 (e.g., over are 2.8 case are •.&. Crosses = over residuals I the of measured and at 42.5° ± measurements Astrophysics X • also the the 3.0 data k present m phase I 0.15) the are very = = m x_ • Mariner Martian .32 k (Harris indicated - 3.2 - 0. - surface 2.7 1.3 1.9 = are of proportional 0.75) describes angle 1.0 75, X small by o. a shown qualitative 10-a For m 42~ of Coffeen fits Data 1961); encounters of surface = phase bright 5. for other , the their the 1.0 in Filled to System volcanic Table relation Vol. albedo-\ areas are the (1965). planet. angles. values is lunar argu­ circles (13) not 163 ex­ on by 1. 1971ApJ...163..121I by April19 be from The m rX TX signals 1961), and instant. minute guiding the establishing were in 1 From No.1, © FIG. Irvine hour 4 4 Data = The negative, the • : American Values time value d.c. 1.0 the made; 2.-Polarization Table at the 1971 value before from Mercury et by from optics, Poor 0300....0330 components are TA run on at. standard TX of 4 minute, (1968). 1 the of the it 4 the Mercury ( = the seeing of Astronomical it the m = is and TX\ appears sky April areas aperture derived 0 data run -0.10 more hours setting is error then which POLARIZATION of and but not background, of of m m m m - ~10 :te N 8 - 0 z ~ ...J <( a.. 0 0::: were was under Mercury 18, U.T. appropriate the 1970 = = = = that ± ~2 excluded guiding of measuring there in 0 4 6 2 of 1.6 diameter and is 0.07 0.32 0.54 0. 1 o 0.05) Society Crosses signal, this Mercury taken .60 larger being April19 72 the or the at -1.8 also WAVENUMBER was way ± X • ± ± ± 2 difficulties phase curves uncertainty X at WAVELENGTH are then minutes. approximately 0.005. but 0.06' 0.09, 0.04, 0.03, 2.0 • than to with no the was .50 10- the are Provided are proportional itself. • OF X use angle it difficulty X locating •DIRECT 4 sky on . 2.4 2.2 5 the shown shown Lyot's (ALBEDO)- about The was (~m) MARS percent l the the 105°. Only produced The again. rX rX TA r'/1. standard in possible results (,u.m)-1 data 4 4 by 4 4 4 recorder OBSERVATION below in m 15". ' M = = = measurements = .40 (,um) to Mercury Filled sky integral AND the i establishing 2.6 one-half level accounts Figure albedo- 0.15 The 0.10 0.05 0.00 l to b of NASA Each background large circles = to error with find 2.8 X • analyzing of MERCURY integration X (~m) chart. X X determine (4.6 1 .35 2. measurements , significance. photoelectrically based X • 10- hour measurement m 10- fluctuations w- for These the 3.0 Astrophysics in are 4 ± and 4 equation this ; 4 4 a observations in corresponding • on ; ; 0.3) 35 after these data visible decreased b photometry background time the percent for X sunset, Since data agree ratio given in (13). 10- Data was of light was taken both polarization or uncertainty 3 for TA with noticeably of of 5 • System values values less made with 4 sec, (Dollfus Mercury the the the on cannot at those 1970 than (15) (14) case any and two a.c. 127 the by of of 1971ApJ...163..121I means haze opposition, itself, Martian sidered clusion. component The ing the these molecular pared angle the powders. from uncertainty for and Thus, their the the portant limit is Mercury to respond most (Leighton 128 © very The As It It the the to surface disappearance American atmosphere. Earth, albedo Rayleigh-scattering (blue is effect is silicate powders, on the approaches stated observations. with and to radio-occultation rX that Earth's possible optical significant unlikely close assumption On to the 4 atmosphere the Mariner is These atmosphere = et clearings) is pressure various the on in the which is shown and the in value earlier, extent al. 1.9 not to Astronomical the this the wavelength m. depth Martian atmosphere to other zero. as 1969). results the X The 0.14 due zero. UPPER same implies H• present of occultation estimate This that analysis. of in a choices 10- in on The that * there surface may consists Mariner result Expressed Neither Table rX latter to hand, reported the and for If Mercury, 4 However, the as estimate, 4 provide is LIMIT atmosphere (J.tm) obscuration the agreement optical the for also which analysis MODELS that observations. is in that of that of Society value of the 0.41 If (Goody douds case, 2. features no surface blue Mercury: very in 4 of the the of this spacecraft ANDREW be experiments. These ON the r'A is light surface here millibars. which Mercury pure evidence strong m depth these 4 5.6 for and derived a light assumed corresponding haze THE not < cloud OF was polarization good falls • surface in V. various 1964), with mb, is of areas is Provided in by 0.1 numbers C02, MERCURY'S 0.28 that the enough has SURFACE results CONCLUSIONS almost scattered, and that pressure TABLE Mercury for small circumstantial in the In agreement particles the with X of is detected for P. Dollfus Martian been the the brighten the Mercury phenomenon. composition according blue general, blue the devoid The models unusual 10- atmosphere. INGERSOLL the even was an transparent. is value by value range are 2 PRESSURE* study. 4.3 relation 4 measured on He clearings known to ATMOSPHERE resembles upper (blue uncertainty surface the they (J.tm) are and prescribed for Mars, atmosphere a at of a with of if more for is of (3), NASA conditions high to general small, any the 4 these haze) the rX will Focas therefore limit the evidence the • of (2) about 5.8 these Ne 4 it Blue pressure the were and FOR Occasional than cloud for < atmosphere. Mercury's shortest appear If cloud the surface between surface is surface Astrophysics planets' is they on 0.1 surface-pressure of possible in this (1969) atmospheric the VARIOUS to observations. clearings atmospheric a surface of these dark are about particles on any the property place less X that on will Moon model 0.65 on as pressure pressure Ar often Mars wavelengths, 10- surface atmospheres. way; areas clouds part supports than Mars the lifting atmosphere. appear to Mars an 35 4 occur Data and is place (,um) are observed upper percent at the limb of of 0.001 the haze, correct, as is phenomena, polarization on correspond­ to pressure the of has the the for large Moon very System as mainly 4 the estimates most an this Mercury evaluate and of the limit Vol. time surface surface part silicate of is a due which upper phase If Mars com­ from close pure then blue con­ con­ (16) that cor­ and im­ 163 the on on at to of of 1971ApJ...163..121I Pollack, Slipher, O'Leary, Leighton, Pettengill, Morozhenko, Minnaert, Kliore, Kliore, --. Irvine, Harris, Gehrels, Dollfus, Belton, Appenzeller, Goody, Goldstein, Dollfus, Coffeen, James grant research fore mosphere is wavelengths. the No.1, (Slipher © 414. B. sity 1243. A.J., of small, I Finally, increase American should the Chicago A., W. A., of NGL-05-002-003. A., D. 1971 M. R. E. 1969, A. J. A. A., T., 73, D. B. Davies, R. surface Chicago 1962). M. was L. R. G. M., Cain, B. the Fjeldbo, C. M. 1961, J. Westphal is L. T., and Coffeen, 251. I. B., it A. like 1961, 1970, H., S., 1967, Astr. 1962, 1941, a Press), in Simon 1965, 1964, 1966, should surface and supported At significant V. Focas, Horowitz, D. Astronomical in and M. Counselman, the to Press), of in 3200 1970, and Planets Radio Icarus, G., The C., Ap. Rea, A.J., Atmospheric T., Zs.f. E., chap. T., Hunten, thank Planets Mars number POLARIZATION for J. Levy, be Seidel, Ap., 1., Photographic and is and Menzel, Soviet D. A Sci., chap. 1966, 70, noted N.H., Ap., and 7, also 9. instruction 93, the by fraction G. 2, Owings, is Leovy, Sol and 42. G. 403. D. B. 5, C. Satellites, 403. 63. Astr.-A1, 1967, C.R., extremely 8. of 64, surface Society the S., very Radiation 475. D. Satellites, L. L., M. Murray, C., that blue 269. Eshelman, H., C. and Giles National Story 1969, D. B Rainville, Ap. of dark. although 262, B. Charon, ed. 1964, clearings in albedo the Rasool, • 1., REFERENCES B. 1969, Science, of 13, ed. for I. Provided dark various OF G. 1024. 148, Mars total C., This Theoretical 852. A.J., V. G. P. building L. Aeronautics Science, MARS J., Sharp, is S. R., P. Kuiper 249. in the P., 166, (Flagstaff, at light only Lecomte, I. 69, means Kuiper Fjeldbo, the aspects and 1969, by optical opposition 225. 826. R. 166, Basis AND 0.6 and scattered ultraviolet. the the Shapiro, P., and Science, that 49. G., of B. NASA Ariz.: G., equipment of Herriman, and depth (London: MERCURY B. the M. Griboval, and observational the I. I. M. would Middlehurst Northland Space 166, planetary by Astrophysics Drake, of Middlehurst light 1969, the 1393. Oxford the A. P., used be Administration H., planet F. Martian scattered A.J., and much Press), D. Young, albedo, University (Chicago: in astronomy. Young, 1965, 74, (Chicago: Data this at less chap. 461. the atmosphere A. Science, by and study A. System dramatic T., University Press), shortest 5. T. the Univer­ there­ under Smith, This 1968, and 129 149, at­ p. 1971ApJ...163..121I © American Astronomical Society • Provided by the NASA Astrophysics Data System