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THE MINOR

BULLETIN OF THE MINOR SECTION OF THE BULLETIN ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS

VOLUME 33, NUMBER 1, A.D. 2006 JANUARY-MARCH 1.

LIGHTCURVE AND Observatory (Observatory code 926) near Nogales, Arizona. The DETERMINATION FOR 4006 SANDLER observatory is located at an altitude of 1312 meters and features a 0.81 m F7 Ritchey-Chrétien telescope and a SITe 1024 x 1024 x Matthew T. Vonk 24 micron CCD. Observations were conducted on (UT dates) Daniel J. Kopchinski January 29, February 7, 8, 2005. A total of 37 unfiltered images Amanda R. Pittman with exposure times of 120 seconds were analyzed using Canopus. Stephen Taubel The lightcurve, shown in the figure below, indicates a period of Department of Physics 3.40 ± 0.01 and an amplitude of 0.16 . University of Wisconsin – River Falls 410 South Third Street Acknowledgements River Falls, WI 54022 [email protected] Thanks to Michael Schwartz and Paulo Halvorcem for their great work at Tenagra Observatory. (Received: 25 July) References

Minor planet 4006 Sandler was observed during January Schmadel, L. D. (1999). Dictionary of Minor Planet Names. and February of 2005. The synodic period was Springer: Berlin, Germany. 4th Edition. measured and determined to be 3.40 ± 0.01 hours with an amplitude of 0.16 magnitude. Warner, B. D. and Alan Harris, A. (2004) “Potential Lightcurve Targets 2005 January – March”, www.minorplanetobserver.com/ astlc/targets_1q_2005.htm Minor planet 4006 Sandler was discovered by the Russian astronomer Tamara Mikhailovna Smirnova in 1972. (Schmadel, 1999) It the with an that varies between 2.058 AU and 2.975 AU which locates it in the heart of the main belt. The asteroid was chosen from a list of suggested targets provided by the CALL website (Warner 2004).

Sandler was observed during the spring of 2005 by three University of Wisconsin—River Falls students (Kopchinski, Pittman, Taubel) and a professor (Vonk) utilizing the Tenagra

EDITORIAL ANNOUNCEMENT: NEW MPB ASSISTANT EDITOR NAMED

With the increase in the number of articles received and the commensurate slowing in turnaround time by the Editor, the need for an Assistant Editor has become apparent. On behalf of the Minor Planets Section Recorder and the staff of the Minor Planet Bulletin, it is a pleasure to announce the appointment of Brian D. Warner to the position of Assistant Editor. As the title suggests, Warner will assist the Editor with the processing and review of submitted manuscripts. All submitted manuscripts and editorial correspondence should continue to be addressed to the Editor. Please join in thanking Brian for taking on this new role for the benefit of the Minor Planet Bulletin and its readers.

Minor Planet Bulletin 33 (2006) Available on line http://www.minorplanetobserver.com/mpb/default.htm 2

CLOSE MUTUAL APPROACHES OF The table gives the following data: MINOR PLANETS IN 2006 1. Date: date and time of closest geocentric approach (in U.T.). All other information is given for this instant. Edwin Goffin 2. Closest approach: gives the minimum geocentric distance (in Aartselaarstraat 14 seconds of arc) and the position angle (in degrees) of the nearest B-2660 Hoboken (Antwerpen) minor planet with respect to the farthest one. Belgium 3. Minor planet 1: information on the nearest minor planet: [email protected] • number and name visual magnitude, • parallax in seconds of arc, (Received: 30 March) • apparent motion in seconds of arc per , • position angle of the direction of motion in degrees. 4. Minor planet 2: information about the farthest minor planet. Tabulated are 41 cases where one minor planet comes to The same data as for the nearest one are given. In addition the within 120" of another and both are magnitude 16 or right ascension and declination (2000) are printed. brighter. A challenge for minor planet observers! 5. Sun and : • of the Sun in degrees, Here I present a list of close approaches between numbered minor • elongation of the Moon (degrees), planets larger than 40 km during 2006 where: • illuminated fraction of the Moon in %. • the elongation of the Sun is more than 30°, • both minor planets are brighter than visual magnitude 16, The author acknowledges the Computer Center of Agfa-Gevaert • and the minimum geocentric separation is less than 120". N.V. (Mortsel, Belgium), site of the computations.

Close mutual approaches of minor planets

======" 0 (Dist. < 120 ; El. Sun > 30 ; magn. < 16.0)

D a t e (U.T.) Min. Pos. M i n o r p l a n e t 1 M i n o r p l a n e t 2 dist. ang. N a m e Vis. Hor. Motion N a m e Vis. Hor. Motion Right Decli- Elon- Ill. mag. par. per pos. mag. par. per pos. ascens. nation gation frac. hour ang. hour ang. (2000.0) (2000.0) Sun Moon Moon

h m " 0 " "/h 0 " "/h 0 h m 0 ' 0 0 % 2006 jan 12 9 47.7 75.18 7 11.00 5.58 34.32 72 14.68 3.69 18.49 45 2 31.94 +13 39.2 108 51 95 jan 22 11 56.8 19.40 22 12.96 2.28 52.71 71 15.65 2.01 44.36 61 22 33.01 - 7 32.0 34 127 52 feb 5 3 34.8 67.61 232 11.17 4.33 13.00 54 16 10.70 4.02 13.27 64 4 36.41 +18 37.4 114 27 48 feb 26 2 35.5 62.76 24 1119 Euboea 15.63 4.59 11.34 103 13.65 2.63 2.21 5 14 33.54 - 8 08.9 118 91 6 mar 7 6 34.1 91.56 149 15.26 2.86 46.14 76 15.74 2.07 29.49 86 18 33.36 -21 12.9 68 160 54

mar 8 8 32.7 32.22 197 13.65 3.06 51.72 75 13.39 2.86 46.05 70 3 22.99 +14 15.9 64 44 65 mar 16 8 25.8 111.41 159 14.95 3.35 71.13 75 13.27 2.98 58.28 76 3 04.62 +18 16.4 53 141 98 apr 3 1 13.9 8.32 358 14.79 3.47 31.67 97 579 Sidonia 13.78 2.87 22.02 101 7 07.36 +30 07.7 91 37 26 may 3 10 11.0 79.91 67 10.29 3.65 32.73 64 492 Gismonda 15.02 3.54 33.24 78 20 45.62 -19 38.0 94 159 34 may 7 13 46.7 3.58 156 15.25 2.39 59.12 78 14.70 2.07 47.50 81 5 02.55 +11 17.4 30 86 72

may 13 9 10.8 92.37 100 14.00 3.08 55.55 64 12.42 2.88 49.58 76 23 31.79 - 6 15.5 61 118 99 may 20 16 48.6 70.51 334 15.88 3.01 72.42 66 13.46 2.14 45.90 68 1 10.23 + 7 07.7 40 45 46 ? may 31 9 45.9 1.07 68 13.87 3.27 35.11 114 14.48 2.85 29.38 103 10 09.53 + 5 27.3 82 32 19 may 31 16 48.6 46.09 230 15.18 2.72 64.99 102 14.60 2.61 61.45 99 7 15.68 +25 06.0 37 23 22 jun 11 6 40.5 95.56 314 13.41 3.15 62.67 63 14.53 2.94 55.32 66 1 18.01 + 8 57.6 58 126 98

jun 14 12 43.1 9.84 152 337 Devosa 13.71 3.62 45.36 63 15.94 2.79 32.28 63 0 11.13 - 1 25.6 81 63 89 jun 30 16 46.9 56.77 358 13.54 2.97 65.65 102 15.91 2.33 44.91 108 9 52.58 + 7 13.5 49 9 24 jul 4 8 37.2 26.80 192 12.87 3.17 77.22 107 14.43 2.29 49.67 110 9 42.94 +12 17.5 41 55 56 jul 13 13 2.2 29.62 311 369 Aeria 13.27 4.02 44.75 84 14.70 2.96 34.55 104 1 43.07 - 4 07.1 88 62 91 aug 6 8 34.2 41.69 44 15 Eunomia 8.46 5.92 37.04 275 11.47 4.85 29.53 262 20 23.70 -13 58.4 169 34 86

aug 6 16 22.2 97.29 72 15.38 3.96 17.52 273 483 Seppina 13.43 3.72 18.72 223 23 12.35 + 2 15.9 143 72 88 aug 10 9 32.2 60.91 174 1072 Malva 15.70 2.95 67.11 86 15.35 2.33 45.61 87 6 05.53 +27 17.0 46 119 98 sep 9 15 30.4 81.26 212 14.85 2.86 73.07 115 15.63 2.13 48.19 111 13 21.87 - 2 46.0 33 173 95 sep 10 19 18.5 62.90 19 14.31 3.20 75.40 102 15.18 2.25 45.13 96 8 22.80 +20 08.9 44 93 87 sep 25 5 51.5 107.63 135 15.19 2.79 46.38 100 15.60 2.48 40.32 116 16 28.42 -14 59.6 66 36 7

sep 27 9 21.3 96.06 230 15.14 2.29 51.27 117 15.04 2.00 41.10 110 10 04.77 +13 02.8 35 88 21 oct 14 19 3.8 67.43 315 12.47 5.08 31.11 245 738 Alagasta 14.80 3.93 28.50 247 0 33.96 - 1 04.8 165 112 42 oct 25 11 11.2 24.65 16 13.30 4.21 53.06 117 15.68 2.75 31.02 125 8 37.52 + 8 35.2 82 120 11 oct 31 14 35.1 44.47 328 15.70 2.81 35.58 54 15.87 1.62 17.65 49 20 14.66 -30 42.6 81 37 69 nov 12 1 5.8 24.45 260 14.33 2.62 52.43 110 13.64 2.44 47.74 98 12 15.56 + 7 13.8 49 52 56

nov 16 8 30.5 110.66 41 1032 Pafuri 15.92 2.35 56.12 111 13.15 2.29 52.47 110 13 22.95 - 1 13.3 34 18 18 nov 19 18 32.1 30.17 36 15.54 2.43 28.51 112 15.63 2.05 22.39 108 10 40.67 +10 42.7 79 66 2 nov 27 16 5.3 91.49 6 15.46 2.86 58.30 77 1332 Marconia 15.85 2.73 54.20 76 20 09.45 -21 55.9 54 30 44 dec 20 14 49.6 111.07 133 14.08 4.91 32.31 253 14.44 3.35 22.99 268 4 20.59 +17 10.9 157 155 2 dec 27 20 18.8 41.29 11 14.94 3.06 57.75 78 14.38 2.62 46.54 72 22 22.92 - 8 51.3 58 35 53

Minor Planet Bulletin 33 (2006) 3

ASTEROID-DEEPSKY APPULSES IN 2006 The table gives the following data:

Brian D. Warner Date/Time Universal Date (MM DD) and Time of closest Palmer Divide Observatory approach 17995 Bakers Farm Rd. #/Asteroid The number and name of the asteroid Colorado Springs, CO 80908 [email protected] RA/Dec The J2000 position of the asteroid AM The approximate visual magnitude of the asteroid (Received: 4 September) Sep/PA The separation in arcseconds and the position angle The following list is a very small subset of the results of a search from the DSO to the asteroid for asteroid-deepsky object appulses for 2006, presenting only the DSO The DSO name or catalog designation highlights for the based on close approaches of brighter DM The approximate total magnitude of the DSO to brighter DSOs. The complete set of predictions is Type The type of DSO: OC = Open Cluster; GC = available at: ; G = Galaxy http://www.minorplanetobserver.com/htms/dso_appulses.htm SE/ME The elongation in degrees from the sun and moon For any event not covered, the 's web site at respectively http://scully.harvard.edu/~cgi/CheckMP allows you to enter the MP The phase of the moon: 0 = New, 1.0 = Full. location of a suspected asteroid or supernova and check if there Positive = waxing; Negative = waning are any known targets in the area.

Date UT # Name RA Dec AM Sep PA DSO DM Type SE ME MP ------01 01 21:52 174 Phaedra 10 51.32 + 8 18.1 13.6 72 273 NGC 3427 13.2 G 120 145 0.047 01 29 08:19 07 59.41 +27 03.6 12.6 98 7 NGC 2492 12.7 G 166 171 -0.001 02 21 17:34 148 Gallia 06 31.12 + 5 55.3 12.0 163 275 Cr 97 5.4 OC 123 143 -0.454 02 24 11:51 11 32.41 - 9 57.5 11.1 32 18 NGC 3723 14.0 G 155 107 -0.174 03 01 22:29 10 44.11 +11 46.2 13.9 271 20 M95 9.7 G 175 150 0.055 03 06 08:30 12 49.51 -10 06.5 11.5 102 72 AN 3 11.6 G 150 126 0.451 03 25 05:48 12 27.34 + 9 26.7 11.9 53 41 NGC 4424 11.7 G 169 124 -0.236 03 25 22:55 194 Prokne 12 26.78 + 9 33.9 11.9 167 221 NGC 4417 11.1 G 168 134 -0.168 03 27 00:10 10 01.72 +33 10.3 13.6 137 6 UGC 5393 14.0 G 131 160 -0.084 04 03 22:47 12 27.53 - 8 08.6 11.3 85 18 NGC 4428 12.6 G 174 104 0.347 04 23 09:26 202 Chryseis 12 15.58 + 9 35.0 11.9 64 199 NGC 4207 12.5 G 145 152 -0.251 04 23 08:58 105 Artemis 12 21.43 + 4 36.7 11.2 127 70 NGC 4292 12.2 G 150 149 -0.253 05 05 03:39 15 13.62 -15 32.8 13.3 183 203 NGC 5892 11.7 G 174 96 0.495 05 21 23:54 11 07.14 +18 33.3 12.8 67 234 UGC 6171 13.9 G 100 164 -0.317 05 21 10:42 13 12.98 +18 05.5 13.2 280 165 M53 7.7 GC 125 147 -0.378 05 27 12:31 22 03.52 -20 20.7 13.9 46 162 NGC 7188 13.2 G 100 104 0.003 05 29 07:43 21 27.13 -60 03.2 13.9 181 242 NGC 7059 11.9 G 116 135 0.053 06 19 16:56 15 42.36 -13 11.8 12.6 136 343 NGC 5978 14.0 G 148 136 -0.372 06 20 09:24 13 33.21 - 1 01.9 13.2 9 45 NGC 5211 12.3 G 113 170 -0.298 06 20 08:09 202 Chryseis 12 22.33 + 7 09.7 12.9 48 33 NGC 4309 12.7 G 93 158 -0.304 07 20 01:01 19 44.85 -14 41.9 11.6 193 346 NGC 6822 8.8 G 173 120 -0.260 07 21 10:26 19 28.05 -38 50.5 13.0 180 42 NGC 6794 12.9 G 160 145 -0.142 07 21 23:00 14 13.41 + 7 37.0 11.4 251 224 NGC 5514 12.7 G 90 123 -0.106 07 23 03:01 18 12.92 +21 20.7 9.6 273 134 NGC 6580 14.0 G 130 130 -0.044 07 25 20:42 20 32.98 + 9 55.9 13.3 234 355 NGC 6930 12.8 G 150 148 0.005 07 26 02:01 631 Philippina 20 32.80 + 9 55.6 13.3 38 355 NGC 6928 12.2 G 150 149 0.009 08 17 15:56 1631 Kopff 22 39.20 -22 42.4 13.4 82 177 NGC 7341 12.4 G 165 102 -0.330 08 20 14:13 508 Princetonia 00 24.43 -13 57.8 13.2 55 148 NGC 102 14.0 G 144 112 -0.095 08 21 01:21 17 39.90 -32 10.3 13.4 220 312 M6 4.2 OC 118 148 -0.069 08 22 21:17 20 53.50 -12 32.5 13.9 28 179 M72 9.4 GC 162 169 -0.007 08 22 14:53 23 01.84 + 2 14.5 13.4 97 160 NGC 7460 13.0 G 160 147 -0.013 08 22 02:37 21 46.49 -21 11.8 12.0 133 356 Pal 12 12.9 GC 170 168 -0.026 08 27 14:21 11405 1999 CV3 22 23.55 -32 20.4 13.8 115 101 NGC 7262 13.8 G 158 126 0.124 08 29 15:26 916 America 23 30.92 + 3 32.6 12.9 39 27 NGC 7687 13.4 G 160 135 0.278 09 17 14:26 01 24.76 + 9 55.8 12.3 255 168 NGC 522 12.9 G 151 98 -0.201 09 22 17:23 02 23.99 +27 20.9 13.6 10 212 NGC 904 13.6 G 135 138 0.001 09 26 07:12 881 Athene 00 22.39 +29 44.6 13.3 36 339 NGC 97 12.3 G 151 147 0.128 09 28 07:15 593 01 33.03 -16 32.9 13.3 59 156 NGC 594 14.0 G 154 120 0.284 10 20 13:57 01 23.45 + 9 22.9 12.8 189 167 NGC 509 13.4 G 176 166 -0.023 10 22 13:12 04 33.17 + 5 22.8 13.0 114 345 UGC 3087 13.7 G 139 141 0.002 10 23 11:29 206 Hersilia 00 27.89 - 1 45.2 12.7 251 336 NGC 124 13.0 G 156 141 0.016 10 24 08:05 206 Hersilia 00 27.35 - 1 48.7 12.7 111 156 NGC 118 14.0 G 155 130 0.044 10 26 22:40 2430 Bruce Helin 02 39.39 + 6 34.6 14.0 179 28 NGC 1026 12.6 G 169 131 0.207 10 27 00:37 619 Triberga 03 08.26 + 4 09.3 13.1 182 318 NGC 1218 12.7 G 162 134 0.213 11 16 10:41 02 27.60 - 0 14.8 12.6 50 184 NGC 934 13.1 G 156 146 -0.176 11 20 00:34 01 19.82 +14 49.8 13.2 181 338 NGC 471 13.3 G 146 157 -0.008 11 21 13:12 02 34.86 +32 51.4 12.3 58 126 NGC 978A 14.0 G 159 157 0.006 11 27 02:56 09 40.49 + 3 30.8 11.8 214 206 NGC 2960 12.4 G 98 166 0.373 12 27 03:27 12 27.00 + 2 27.6 13.7 141 180 NGC 4420 12.1 G 90 172 0.447

Minor Planet Bulletin 33 (2006) 4

LIGHTCURVE ANALYSIS OF ASTEROIDS compilation by Harris and Warner (2005). 326, 329, 426, 619, 1829, 1967, 2453, 10518 AND 42267 Notes on the results: The 14.446h period found for is Donald P. Pray somewhat longer than the 14.184h value (Gil Hutton 1993) listed Carbuncle Hill Observatory in the Harris and Warner compilation. A 14.184h period is not a P.O. Box 946 possible solution for the current data set. The difference may well Coventry, RI 02816 be explained because the current data set contains about six times [email protected] as many points as the Gil Hutton data. 329 Svea had a previously determined period approximated at 15h (Weidenschilling et al. (Received: 7 October Revised: 7 November) 1990). The currently derived period of 15.201±0.005h is a refinement of this. The period of had been estimated by Mohamed, et al. (1995), to be >32h. The finding of 34.3±0.2h Lightcurve period and amplitude are reported for nine reported here confirms this estimation. For 619 Triberga, the asteroids observed at Carbuncle Hill Observatory during previous period of 13.95h (Binzel, 1987) was based on sparse, March 2005-September 2005: 326 Tamara, non-overlapping lightcurve points taken over a four-night span. 14.446±0.002h, 0.10m; 329 Svea, 15.201±0.005h, The more extensive data taken here, are not compatible with this 0.09m; 426 Hippo, 34.3±0.2h, 0.22m; 619 Triberga, previous value, but fit a longer period of 29.412±0.003h. 29.412±0.003h, 0.40; 1829 Dawson, 4.254±0.001h, 0.28m; 1967 Menzel, 2.8350±0.0005h, 0.28m; 2453 Thanks are given to Brian Warner for his continued development Wabash, 6.878±0.001h, 0.67m; (10518) 1990 MC, and improvement of the program, “Canopus”. 6.613±0.003h, 0.08m; (42267) 2001 QJ81, 3.1520±0.0005h, 0.15m. References

Binzel, R. P. (1987). Icarus 72, 135-208. Carbuncle Hill Observatory, MPC code I00, is located about twenty miles west of Providence, RI, in one of the darkest spots in Gil Hutton, R. G. (1993). Rev. Mexicana Astron. Astrof. 25, 75- this diminutive state. Observations were made using two 77. CCD/telescope systems housed in separate buildings. One was a SBIG ST-10XME CCD camera, binned 3x3, coupled to a 0.35m Harris, A. W. and Warner, B. D. (2005). “Minor Planet f/6.5 SCT. The other was a SBIG ST-7ME CCD camera, binned Lightcurve Parameters”, found on the Minor Planet Center web 1x1, coupled to a 0.25m f/4 Schmidt-Newtonian. These systems site: http://cfa-www.harvard.edu/iau/lists/LightcurveDat.html. produce image dimensions of 21x14 arcmin (1.9 arcsec per pixel), and 23x16 arcmin (1.8 arcsec per pixel), respectively. All Mohamed, R.A., Krugly, Yu. N., and Lupishko, D. F. (1995). observations were taken through the “clear” filter. Astron. J. 105, 1877-1879.

Seven asteroids, 326 Tamara, 329 Svea, 426 Hippo, 619 Triberga, Pravec, P. (2005). Photometric Survey of Asynchronous Binary 2453 Wabash, (10518) 1990MC, (42267) 2001 QJ81 were Asteroids, http://www.asu.cas.cz/~asteroid/binastphotsurvey.htm. selected from the “CALL” website’s “List of Potential Lightcurve Targets” (Warner 2005). Two other asteroids, 1829 Dawson and Warner, B. D. (2005). Collaborative Asteroid Lightcurve Link 1967 Menzel were selected from a list provided by Pravec (2005) (CALL) web site. as part of his Photometric Survey of Asynchronous Binary http://www.MinorPlanetObserver.com/astlc/default.htm. Asteroids study. Image calibration via dark frames, bias frames and flat field frames was performed using “MaxIm DL”. Weidenschilling, S. J., Chapman, C. R., Davis, D. R., Greenberg, Lightcurve construction and analysis was accomplished using R., Levy, D. H., Binzel, R. P., Vail, S. M., Magee, M., and Spaute, “Canopus” developed by Brian Warner. Differential D. (1990). Icarus 86, 402-447. was used in all cases, and all measurements were corrected for light travel time.

Results are shown in the table below. Column headings are self- explanatory. Plots of the lightcurves are also presented. Five of the asteroids, 326, 329, 426, 619 and 1829, have been previously studied by other observers, but none have a U>2 as listed in the

Observation Date Range Period PE Amplitude Phase angle # Name (2005) Sessions Images (h) (h) (m) Range 326 Tamara 03/22-05/11 9 468 14.446 0.002 0.10 15.1 - 14.4 329 Svea 03/14-04/15 10 366 15.201 0.005 0.09 7.0 -9.3 426 Hippo 09/02-09/08 7 521 34.3 0.2 0.22 4.7 - 4.8 619 Triberga 06/08-08/11 10 260 29.412 0.003 0.40 9.2 -21.0 1829 Dawson 09/11-09/13 3 110 4.254 0.001 0.28 4.3 - 4.5 1967 Menzel 09/23-09/25 3 193 2.8350 0.0005 0.28 13.0 - 12.0 2453 Wabash 09/08-09/22 4 167 6.878 0.001 0.67 8.6 - 2.7 10518 1990MC 08/24-09/02 5 165 6.613 0.003 0.08 9.4 -7.6 42267 2001 QJ81 09/11-09/30 5 159 3.1520 0.0005 0.15 2.4 - 11.2

Minor Planet Bulletin 33 (2006) 5

Minor Planet Bulletin 33 (2006) 6

LIGHTCURVE ANALYSIS FOR (6327) 1991 GP1 From the onset, it appeared that the asteroid had a long period. It took a number of sessions covering a large range of dates to Brian D. Warner finally obtain sufficient data to form a likely solution. Data from Palmer Divide Observatory two sessions taken in early May at PDO were not included since 17995 Bakers Farm Rd. doing so prevented any solution from being found. It is not Colorado Springs, CO 80908 believed that the excluded data provided evidence of unusual [email protected] behavior, such as non-principal axis (NPA) rotation. This is based in large part by being able to fit all other sessions into the Robert K. Buchheim proposed solution. Altimira Observatory (G76) 18 Altimira, Coto de Caza, CA 92679 Each of us found a variable in the asteroid field. Buchheim’s [email protected] variable star turned out to be the more unusual find, a large amplitude Delta Scuti with multiple periods. Warner’s variable (Received: 12 July) was noted in the All Sky Automated Survey (2005), ASAS 162277+0437.0, but only 16 observations had been reported. Detailed follow up observations by Warner showed it to be a W For asteroid (6327) 1991 GP1 we find a synodic lightucrve period of 18.199±0.005 hr and an amplitude UMa eclipsing binary with a period of about 11.8h. Either case of 0.06±0.02 mag. Independently, both of us discovered serves as an excellent example of getting as much data as possible previously unreported or poorly studied variable in from every image. the field with the asteroid, one being a Delta Scuti References variable and the other being a known W Uma eclipsing binary catalogued as ASAS 162277+0437.0. Harris, A.W., Young, J.W., Bowell, E., Martin, L.J., Millis, R.L., Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne, H., and Zeigler, K.W., (1989). “Photoelectric Observations of By coincidence, both authors started working on (6327) 1991 GP1 at the same time. Buchheim “ceded” the asteroid to Warner but Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186. contributed two critical nights that lead to finding the lightcurve solution. Palmer Divide Observatory consists of three telescopes, All Sky Automated Survey web site: one 0.5-m Ritchey-Chretien and two 0.35-m SCT telescopes. For http://archive.princeton.edu/~asas/. 2005. this asteroid, the 0.5m scope was used with a Finger Lakes Instrumentation CCD (1001E) chip running at –30°C. Exposures were 120s. Altimira Observatory observations were made with a 0.28-m SCT and an SBIG ST-8XE NABG.

The table below shows the important observation details. Column 3 gives the phase angle for the date. Columns 4 and 5 give the Phase Angle Bisector (PAB) longitude and latitude respectively.

Obs Date Phase LPAB BPAB PDO 2005 05 13 12.8 241.1 19.9 PDO 2005 05 16 12.3 241.3 19.8 PDO 2005 05 19 12.0 241.6 19.8 Altimira 2005 05 20 11.9 241.7 19.7 Altimira 2005 05 22 11.8 241.8 19.7 PDO 2005 06 01 12.3 242.7 19.2 PDO 2005 06 05 13.0 243.0 19.0 PDO 2005 06 06 13.2 243.1 18.9 PDO 2005 06 07 13.5 243.2 18.9 PDO 2005 06 08 13.7 243.3 18.9 PDO 2005 06 14 15.2 244.0 18.3 PDO 2005 06 15 15.5 244.1 18.2 Table I. The phase and Phase Angle Bisector values for observations of (6327) 1991 GP1 made at the Palmer Divide and Altimira Observatories.

The images at PDO and Altimira were measured with MPO Figure 1. The lightcurve for (6327) 1991 GP . The data are plotted Canopus using aperture photometry. Buchheim used the data 1 against the solution of 18.199 hr. The amplitude is 0.06±0.02 mag. export facility of the program to send his data to Warner, who then The circles around some data points indicate the first observation imported the data into his. This created a single data set for (by increasing JD) in the specific run. The squares represent the analysis. The period was found using Canopus’ implementation of last data point (by JD). a Fourier analysis algorithm developed by Harris (1989).

Minor Planet Bulletin 33 (2006) 7

LIGHTCURVE OF Durkee, R. I., (2005). “Rotational Period Determination for 62 Erato and .” The Minor Planet Bulletin 32, p. 84. Rui M. D. Gonçalves Linhaceira Observatory (938) Harris, A.W., and Warner, B. D., (2003). “Minor Planet Instituto Politécnico de Tomar Lightcurve Parameters”. Posted on the WWW: http://cfa- 2300-313 Tomar, Portugal www.harvard.edu/iau/lists/LightcurveDat.html (2003 December [email protected] 15 update).

Raoul Behrend MPCOrb database http://cfa-www.harvard.edu/iau/MPCORB.html Observatoire de Genève CH-1290 Sauverny - Suisse Tedesco, E. F., (1989). “Asteroid Magnitudes, UBV colors, and [email protected] IRAS and diameters”. In Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, Eds.). University of Arizona Press, (Received: 26 September Revised: 24 October) Tucson.

Warner, B. D., (2004). “Potential Lightcurve Targets 2004: The lightcurve period of 62 Erato is found to be 9.2213 October 1 – December 31”. Posted on the WWW: 0.0007 hours, with an observed amplitude of 0.116 ± ± http://www.minorplanetobserver.com/astlc/default.htm 0.005 mag. Warner, B. D. (2003). A Practical Guide to Lightcurve Lightcurve observations of 62 Erato were made at Linhaceira Photometry and Analysis. Bdw Publishing, Colorado Springs, CO. Observatory during December 2004 and January 2005. Linhaceira roll-of-roof Observatory is located in the center of Portugal, and is MPC code 938. It is equipped with a 0.25 m SCT (F/6.9) with a MX916 CCD. All images were collected unfiltered in 2x2 binning, and pre-processed with bias, dark and flat-field frames. Table I: Observing details for 62 Erato The CCD images were photometric reduced with Herbert Rabb Astrometrica software. Astrometrica is intended to , but Exp. Phase its PSF measurements also give good flux data. Together with a UT Date (sec) Points Coverage (%) set of stars, the differential magnitude asteroid-stars were made 2004 Dec 28 120 120 57 (Warner, 2003). The stamped time was always checked against 2005 Jan 03 120 96 48 German radio standard signal DCF 77, through the sessions. The 2005 Jan 07 120 144 69 CCD images acquisition rate was 15 to 24 hourly. This target was 2005 Jan 17 150 75 56 selected from the Collaborative Asteroid Lightcurve Link (CALL) 2005 Jan 18 125 66 50 2005 Jan 19 125 60 45 website (Warner, 2004), and crosschecked against a list of 2005 Jan 20 125 75 55 lightcurves (Harris and Warner, 2003).

No previous lightcurves have been published for this asteroid, at least at acquisition time (see below). To date, this was the lowest numbered asteroid not having that information. Named after the Greek Muse of poetry, the asteroid was discovered on 1860 Sept. 14 at Berlin by O. Lesser and W. Forster. A diameter of 99.3 ± 2.1 km and an of 0.090 ± 0.004 were determined by Tedesco (1989). The is 8.76 with a slope parameter of 0.15 (MPCOrb). The observing details are listed in Table I. From 2004 Dec. 27 to 2005 Jan. 19, seven sessions were conducted and during that period Erato ranged from 12.6 to 13.2 V magnitude. Using CourbRot (Behrend, 2001) the computed period and lightcurve stack from all seven observational sessions shows a rotation period of 9.2213 ± 0.0007 hours, and an amplitude of 0.116 ± 0.005 magnitude. The computed of maximum brightness is 2004-12-27.966±0.006 UT. These data and conclusion are in perfect agreement with one published recently (Durkee, 2005). Durkee also checked our data results at Behrend site (Behrend) to exclude a different, less likely solution.

References

Behrend, R., (2001). “Réduction d’une courbe de rotation/de lumière”. Orion, 304, 12-15. Figure 1: Each small symbols at the lower left part of the figure represents one night of observations, centered respectively on Behrend, R., http://obswww.unige.ch/~behrend/page1cou.html 2004-12-28, 2005-1-3, 7, 17, 18, 19 and 20.

Minor Planet Bulletin 33 (2006) 8

ASTERIOD LIGHTCURVE ANALYSIS AT HUNTERS HILL calibrations were done in the Cousins R system using Landolt OBSERVATORY AND COLLABORATING STATIONS – (1992) standards to a level of 0.01 mag for Ondrejov data for AUTUMN/WINTER 2005 (6456) and (30825). Modra Observatory is equipped with a 0.6-m f/5.5 reflector and AP8p CCD-camera in its primary focus. FOV is David Higgins 25 arcmin squared with a pixel scale of 1.5 arcsec. Images were Hunters Hill Observatory taken with exposures of 60s with a Clear filter. MaxIm DL was 7 Mawalan Street used for all image calibration. Carbuncle Hill Observatory is Ngunnawal ACT 2913, Australia equipped with 0.35m f/6.5 SCT and SBIG ST-10XME CCD [email protected] camera binned 3x3. This system produced image dimensions of 21x14 arcmin. All observations were taken through the Clear Petr Pravec, Peter Kusnirak filter. MaxIm DL/CCD was used for image calibration with Ondrejov Observatory dark/bias and flat field correction. Ondrejov, Czech Republic Targets were chosen either from the list provided by Warner Gianluca Masi (2005) and from a list of suitable targets provided by Pravec Bellatrix Observatory (2005a), but even the earlier targets chosen from Warner’s list fit Ceccano, Italy with the criteria of the Survey of Asynchronous Binary Asteroids (Pravec, 2005b). Results are summarised in the table below with Adrian Galad, Stefan Gajdos, Leos Kornos and Jozef Vilagi the individual plots presented at the end. Additional comment, Modra Observatory, where appropriate, is provided. Bratislava, Slovakia The strategy of all collaborating stations is to work objects Donald Pray carefully for potential deviations that would indicate the presence Carbuncle Hill Observatory of a . Considerable effort is made to identify and eliminate Greene, Rhode Island USA sources of observational errors that might corrupt the observations (Received: 11 October Revised: 5 November) and lead to false attenuation events. It is particularly important to identify and eliminate data points affected by faint background stars, bad pixels, and cosmic ray hits. Lightcurves for the following asteroids were obtained at Hunters Hill Observatory and four collaborating stations (5386) 1995 TH6: Gianluca Masi of the Bellatrix Observatory, and then analysed to determine the synodic period and observing from Chile, provided additional data.

amplitude: (4949) 1988 WE, (5386) 1975 TH6, 6456 (6456) Golombek: Peter Kusnirak, Ondrejov Observatory, and Golombek, 6556 Arcimboldo, (8567) 1996 HW1, Adrian Galad, Jozef Vilagi and Leos Kornos, Modra Observatory, (12331) 1992 UH6, and (30825) 1990 TG1. provided additional data. Final analysis was performed by Petr Pravec, who determined the refined period and an absolute R

Hunters Hill Observatory is equipped with a 0.36m SCT fitted magnitude estimate of HR = 15.58+0.2, assuming G = 0.15+0.2. with a Meade f/3.3 focal reducer and either a Starlight Xpress

MX716 CCD at f/3 or an SBIG ST-8E CCD at f/4. The targets (8567) 1996 HW1: Peter Kusnirak, Ondrejov Observatory, Don were observed with combinations of 1x1 and 2x2 binning with Pray, Carbuncle Hill Observatory, and Adrian Galad, Jozef Vilagi fixed between -10 and -30 degrees (dependant on and Leos Kornos, Modra Observatory provided additional data. ambient ). Pixel scale at 1x1 binning is 1.32 arcsecs. Petr Pravec found the final period. All observations were made using a Clear filter with guided exposure times ranging from 120 seconds to 300 seconds. MaxIm (12331) 1992 UH6: The target is of such low amplitude that a long DL/CCD, driven by ACP4 and more recently, MPO Connections, period cannot be ruled out. was used for telescope and camera control whilst calibration and image measurements were undertaken by MPO Canopus. (30825) 1990 TG1: Jozef Vilagi and Stefan Gajdos, Modra Observatory, and Peter Kusnirak, Ondrejov Observatory provided Ondrejov Observatory is equipped as described in Pravec et al. additional data. Analysis by Petr Pravec revealed an absolute R

(1998) though they have fitted a new Apogee AP7p. Absolute magnitude estimate of HR = 14.31+0.2, assuming G = 0.15+0.2.

Date Range Period # Name 2005 Sess (hrs) PE Amp U 4949 1988 WE 02 Oct - 10 Oct 4 2.6798 0.0002 0.12 3 5386 1975 TH6 31 Jul - 24 Aug 7 16.841 0.002 0.24 3 6456 Golombek 30 Jul - 25 Aug 10 2.50129 0.00004 0.13 3- 6556 Arcimboldo 23 Sep - 01 Oct 3 2.5159 0.0002 0.16 3 8567 1996 HW1 04 Jul - 05 Jul 6 8.7573 0.0009 0.25 3 12331 1992 UH6 07 Aug - 26 Aug 4 2.727 0.004 0.02 1 30825 1990 TG1 17 Jan - 14 Feb 9 2.62428 0.00005 0.11 3

U values determined by Petr Pravec, Astronomical Institute, Czech Republic

Minor Planet Bulletin 33 (2006) 9

Acknowledgements

Thanks go to Brian D. Warner for his continued development and support for the Equipment Control and Capture software, MPO Connections and the data analysis software, MPO Canopus. The SBIG ST-8E at Hunters Hill was funded by The Planetary Society under the 2005 Gene Shoemaker NEO Grants program. The work at Modra is supported by the Slovak Grant Agency for Science , Grant 1/0204/03 and by The Planetary Society Gene Shoemaker NEO Grant. The work at Ondrejov was supported by the Grant Agency of the Czech Republic, Grant 205/05/0604.

References

Pravec, P. (2005a). Photometric Survey of Asynchronous Binary Asteroids, http://www.asu.cas.cz/~asteroid/binastphotsurvey.htm.

Pravec, P. (2005b). Photometric Survey of Asynchronous Binary Asteroids. In Proceedings of the Symposium on Telescope Science (The 24th Annual Conference of the Society for Astronomical Science), B. D. Warner, D. Mais, D. A. Kenyon, J. Foote (Eds.), pp. 61-67.

Pravec, P., Wolf, M., Sarounova, L. (1998). Lightcurves of 26 near- asteroids. Icarus 136, 124–153

Warner, B. D. (2005). CALL Website, http://www.minorplanetobserver.com/astlc/default.htm.

Minor Planet Bulletin 33 (2006) 10

(Figure 1) and in 2005 (Figure 2). The similarity of the 2001 and 2005 lightcurves is apparent. The peak-to-peak amplitude in 2005 is 0.3 magnitudes, while in 2001 it is at least 0.3 and may be a little more, but the data are scarce. The arbitrary zero phase maximum in 2001 is at JD 2452078.03, while in 2005 it is taken as JD 2453477.900. The composite lightcurve for Sterpin is shown in Figure 3, where the arbitrary zero phase minimum is at JD 2453375.704. Note that full phase coverage has not been achieved.

The 2005 composite lightcurve for 1427 Ruvuma is somewhat noisy (Figure 2) but full phase coverage was achieved and the complete lightcurve was covered on three out of four nights. This is considered a secure result. Sparse data from 2001 is consistent with this period. The peak to peak variation of 0.3 magnitudes implies and axial ratio a/b of 1.32. Ruvuma is a fast rotator compared with most asteroids of less than 50km diameter which have mean rotation rates of 2-3 revs/ (Binzel et al, 1989). The ROTATION PERIODS FOR 1427 RUVUMA composite lightcurve for 2463 Sterpin does not have full phase AND 2463 STERPIN coverage (Figure 3) and this result should be checked at future favourable oppositions. However, we note that phase stacking our Colin Bembrick data with a period of 15.40 hours (Menke, 2005) produces a Mt Tarana Observatory confused lightcurve. The rotation rate for Sterpin is consistent PO Box 1537, Bathurst, NSW, Australia with the mean for asteroids of this size. [email protected] References Bill Allen Vintage Lane Observatory Barbera, R., 2004. “AVE” Analisis de Variabilidad Estelar, 83 Vintage Lane, RD3, Blenheim, New Zealand version 2.51. Grup d’Estudis Astronomics. http://usuarios.lycos.es/barbera/AVE/AveInternational.htm (Received: 22 July Revised: 12 October)

Minor planet 1427 Ruvuma was observed over 4 nights Bembrick, C.S., Richards, T., Bolt, G., Pereghy, B., Higgins, D., in 2005. The synodic period was found to be 4.797 ± and Allen, W.H., 2004. “ – A Slow Rotator”. Minor Planet Bulletin 31, 51-52. 0.003 hours with a peak-to-peak amplitude of 0.3 magnitudes. Similarly, 2463 Sterpin was observed over Binzel, R.P., Farinella, P., Zappala, V., and Cellino, A, 1989. 7 nights, with the synodic rotation being 13.44 ± 0.03 hours and an amplitude of 0.25 magnitudes. “Asteroid Rotation Rates.” In Asteroids II (Binzel, Richard P., Gehrels, Tom and Matthews, Mildred Shapley, eds.) pp. 416-441. Minor planet 1427 Ruvuma (1937 KB) was discovered on 16 May Univ. Arizona Press, Tucson. 1937 by C. Jackson at Johannesburg. It was named after the most important river in southern Tanzania. Minor planet 2463 Sterpin Harris, A.W. and Warner, B.D., 2005. “Minor PLanet Lightcurve (1934 FF) was discovered on 10 March 1934 by G. van Parameters”. Updated February 9 2005. http://cfa- Biesbroeck at Williams Bay. The name was proposed by his www.harvard.edu/iau/lists/LightcurveDat.html daughter in memory of her mother. Both these asteroids are inner main-belt residents, with Ruvuma being about 39 km in diameter Menke, John, 2005. “Asteroid Lightcurve Results from Menke and Sterpin about 13 km diameter. The former has an albedo of Observatory”. Minor Planet Bulletin 32, 85-88. 0.059 while the latter has an albedo of 0.14. No data on these asteroids are to be found in the latest list of rotational parameters 0.2 (Harris & Warner, 2005). However, recently published results for 1427 Ruvuma Period = 4.797 hours Sterpin (Menke, 2005) propose a period of 15.40 hours. 0.3

Minor planet 1427 Ruvuma was initially observed by Bembrick over 3 nights in June 2001. Poor weather on two out of the three 0.4 nights made a period determination uncertain, although a short period appeared likely. Ruvuma was again observed by Bembrick 0.5 in April, 2005. Minor planet 2463 Sterpin was observed by both 2001 authors over 7 nights in January 2005. The observations of Sterpin 0.6 were conducted from two sites – one in New Zealand and one in Australia. The locations of these sites are listed in Bembrick et al Jun-18 (2004). All observations were made using unfiltered differential 0.7 Jun-20 photometry and all data were light time corrected. Jun-24 0.8 Period analysis was carried out using the “AVE” software 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 (Barbera, 2004). The period derived for Ruvuma from the 2005 data was used to compile the composite lightcurves – both in 2001 Figure 1. Composite lightcurve for Ruvuma in 2001.

Minor Planet Bulletin 33 (2006) 11

0.7 0.4 1427 Ruvuma Period = 4.797 hours 2463 Sterpin Period = 13.44 hours 0.8 0.5

0.9

0.6 1.0 Jan-06 Jan-07 2005 0.7 1.1 Jan-08 17-Apr Jan-11 1.2 18-Apr Jan 12a 19-Apr 0.8 Jan 12b 28-Apr 2005 Jan-14 1.3 Jan-15 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.9 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Figure 2. Composite lightcurve for Ruvuma in 2005. Figure 3. Composite lightcurve for Sterpin in 2005.

LIGHTCURVE ANALYSIS OF ASTEROIDS . I observed this asteroid over four nights, 2005 August 78, 126, 522, 565, 714, 1459, 6974 13, 14, 17 and 25. The period found was 7.300 ± 0.001h with an amplitude of 0.15 mag. This period is slightly different from the Domenico Licchelli 7.225 hours reported by Harris & Young, (1989) which was based R. P. Feynman Observatory on a series of observations made in November 1980 when Via Carso 5, 73034 Gagliano del Capo (Le), Italy probably the asteroid showed a nearly polar aspect. [email protected] . Probably this is an asteroid with a shape irregularity. (Received: 12 October) I observed this asteroid over four nights, 2005 August 6, 15, 26 and 27. The best fit of the data suggest a period of 5.366 ± 0.001h and an amplitude of 0.12 mag, in good agreement with that CCD images recorded in October 2004 and July- reported by Dovgopol et al. (1992). September 2005, using a 210mm Dall-Kirkham telescope, yielded lightcurves and periods for eight 522 Helga. For this asteroid Lagerkvist et al. (2001) indicate a asteroids: 78 Diana 7.300 0.001h, 0.15 mag; 126 ± rotation period of 3.4h, but taking into account the size of the Velleda 5.366 0.001h, 0.12 mag; 522 Helga 8.205 ± ± asteroid they suggested also that maybe it was a wrong value. My 0.001h, 0.15 mag; 565 Marbachia 4.587 ± 0.001h, 0.30 data, collected over six nights, 2005 August 15, 27, September 2, mag; 6.998 ± 0.001h, 0.55 mag; 3, 11, and 28 confirmed this hypothesis. The period found was 4.678 ± 0.001h, 0.62 mag; (6974) 1992MC 2.423 ± 8.126 ± 0.001h with an amplitude of 0.35 mag. 0.001h, 0.21 mag. 565 Marbachia. The period of 565 Marbachia reported by Koff et al. (2000), was of 5.084h but in the same article Dr. Pravec notes R. P. Feynman Observatory is located in a very small, but light that there was another possible solution at 4.59h, so I tried to polluted town, in the south of Italy, at about 145m above the sea resolve the ambiguity. I observed this asteroid over four nights, level. Observations were made using a 210mm f/11.5 Dall- 2005 August 9, 13, 14, and 17. The data reveal a lightcurve with a Kirkham telescope and a Starlight SXV-H9 CCD camera, except 4.587 0.001h period with a 0.30 mag amplitude, so Dr. Pravec’s for 1459 Magnya, when I used an old Sbig ST7 ABG camera. All ± suggestion is confirmed. observations were taken through an IDAS clear filter. Image acquisition and standard calibrations were done using Astroart, 714 Ulula. This asteroid has a well known rotation period of published by MSB Software. Photometric measurements and light 6.998h reported in Harris’ list. It was observed in the contest of a curves were prepared using MPO Canopus, published by BDW summer course of , in order to teach the basic Publishing. Differential photometry was used in all cases. differential photometry rules to young students. In effect it is an Asteroids were selected using The Sky, published by Software easy target and its lightcurve is similar to that of some eclipsing Bisque, to locate those that were at an elevation angle of about 30° binary stars like W UMA systems, so it is a good choice for at the beginning of the observations. I only choose asteroids that didactic purpose. had a visible magnitude of 15 or brighter for good signal-to-noise ratio. Then the asteroids were cross-checked with Alan Harris’ list 1459 Magnya. This is an interesting asteroid of the outer Main of lightcurve parameters (Harris, 2005). I only tried to observe Belt, which have a basaltic crust like 4 , (Lazzaro et al. asteroids that did not have previously reported measurements or 2000). It was chosen as a target for the first VLTI observation of had uncertain published results (code 2 in Harris’ list), except for an asteroid in October 2004 (Delbò et al. 2005), so it was observed the case of 714 Ulula. Results are described below. during the same period in order to provide a complete lightcurve and a more precise rotation period of that reported by Almeida et al. (2000) which was based on an incomplete coverage. The data Minor Planet Bulletin 33 (2006) 12 reveal a lightcurve with a 4.678 ± 0.001h period with a 0.62 mag amplitude.

(6974) 1992MC. This asteroid was observed over four nights, 2005 August 10, 14, 15 and 25, when it had a visible magnitude of about 14.6. The data reveal a lightcurve with a 2.423 ± 0.001h period with a 0.21 mag amplitude. Despite of the short rotation period it was a bit difficult to acquire good data because of the low altitude over the horizon and the presence of mist during almost all the observations run.

References

Almeida, R., Angeli, C.A., Duffard, R., and Lazzaro, D. (2001). Astron. Astrophys. 415, 403-406.

Delbò et al. (2005). Icarus submitted

Dovgopol, A.N., Krugly, Yu.N., and Shevchenko, V.G. (1992). Acta Astron. 42, 67-72.

Harris, A.W. (2005). “Minor Planet Lightcurve Parameters” on Minor Planet Center web site: http://cfa- www.harvard.edu/iau/lists/LightcurveDat.html

Harris, A.W. and Young, J.W. (1989). Icarus 81, 314-364.

Koff, R.A., and Brincat, S. F. (2000). Minor Planet Bul. 27, 49-51.

Lagerkvist, C.-I., Erikson, A., Lahulla, F., Di Martino, M., Nathues, A., and Dahlgren, M. (2001). Icarus 149, 190-197.

Minor Planet Bulletin 33 (2006) 13

PROVISIONAL PERIOD DETERMINATION FOR

Frederick Pilcher Illinois College Jacksonville, IL 62650 USA [email protected]

Walter R. Cooney, Jr. 1927 Fairview Dr. Port Allen, LA 70767 USA

(Received: 12 August)

Eleven nights of lightcurves of 264 Libussa indicate a rotation period of 9.238 ± 0.001 hours, or with somewhat less likelihood 18.476 ± 0.002 hours, and amplitude 0.04 ± 0.01 magnitudes.

Minor planet 264 Libussa is listed in Harris and Warner (2005) as having a period 7.056 hours, amplitude > 0.22, and reliability code 2. This study was undertaken to improve the reliability of this result, and found that the listed period requires a large correction.

Differential CCD photometric observations of 264 Libussa were obtained on 11 nights between 2005 Feb 11 and March 18 by Walt Cooney at the Blackberry Observatory, Port Allen, Louisiana, USA (see Cooney and Robinson 2002 for a description), at which Frederick Pilcher was a guest observer for the first two nights. The images were measured and reduced by Pilcher using the Canopus program by Brian Warner. The data fit periods of 9.238 ± 0.001 hours (formal error) and 18.476 ± 0.002 hours equally well, with amplitude 0.04 ± 0.01 magnitudes. Harris (2005) considers the shorter period to be more likely. Figure 1 was constructed by binning 2 adjacent data points separated by not more than 4 minutes, in order to reduce the number of data points from 1809 to 920, and has been phased to 9.238 hours.

Lightcurves at different aspects in future oppositions will be required to definitively distinguish between the shorter and longer periods. Hutton (1990) and Armstrong et al (1996) have published for 264 Libussa amplitudes near 0.2 on the basis of data sets much less extensive than that presented here, and at other aspects. This supports the hypothesis that at the 2005 apparition this object was observed nearly pole-on. Harris (2005) suggests that while the second harmonic of a Fourier series dominates for most asteroid lightcurves, the first harmonic may dominate at a near polar aspect. This argument suggests that the shorter 9.238 hour period may be the correct one. Oppositions at which we urge our readers to obtain additional lightcurves if feasible occur in April, 2006; July, 2007 at –35 degrees declination (southern hemisphere observers please respond); and November, 2008. If lightcurves can be obtained at all of these opportunities it will probably be possible to obtain a shape model, pole position, and accurate sidereal period.

The authors wish to thank Brian Warner for continuing advice and support which made this investigation possible.

References

Armstrong, J. C., Nellermoe, B. L., and Reitzler, L. E. (1996). “Measuring Rotation Periods of Asteroids Using Differential CCD Photometry”. I. A. P. P. P. Communications 63, pp. 59-68.

Minor Planet Bulletin 33 (2006) 14

Cooney, W. R. Jr., and Robinson, L., (2002). “Rotation Periods November 28 it will be 1.5 magnitudes brighter than at any time and Lightcurves of Minor Planets (412) Elisabetha, (547) until the year 2035. has an approximate 3:5 Praxedis, and (7564) 1988 CA”. MPB 29, 78-79. commensurability with Earth, with close approaches every five . These are now becoming rapidly less favorable, and this Harris, A. W., (2005), Personal Communication. planet will not be nearly as bright for the rest of the 21st century as magnitude 13.2 which will be attained August 1. (11405) 1999 Harris, A. W., and Warner, B. D., (2005). “Minor Planet CV3 is brighter at magnitude 12.5 on August 10 and closer at Lightcurve Parameters”. Posted on www: http://cfa- 0.154 AU on July 31 than at any time since and including www.harvard.edu/iau/lists/LightcurveData.html (2005 Feb. 9 discovery, and until the year 2043. This planet is moving rapidly update) southward, being generally better observed from the northern hemisphere before maximum elongation and from the southern Hutton, R. G., (1990), “V+B Photoelectric Photometry of hemisphere afterward. (23187) 2000 PN9 becomes much closer Asteroids 121 Hermione, 264 Libussa, and 354 Eleonora”. MPB and brighter in early March than at any time for the rest of the 21st 17, 41-43. century. It passes inferior conjunction March 5, becomes brightest at magnitude 12.0 two days later after moving 0.020 AU behind the Earth on March 6, then moves rapidly outward and fades to magnitude 16 on March 24. At far northerly declination planet 23187 will be observable only by northern hemisphere observers. (68950) 2002 QF15 reaches magnitude 14.3 on May 19 and minimum distance 0.125 AU on May 13. It will be even brighter and closer in May, 2019.

These lists have been prepared by an examination of the maximum elongation circumstances of minor planets computed by the author for all years through 2060 with a full program written by Dr. John Reed, and to whom he expresses his thanks. Elements are from EMP 1992, except that for all objects for which new or improved elements have been published subsequently in the Minor Planet Circulars or in electronic form, the newer elements have been used. Planetary positions are from the JPL DE-200 ephemeris, courtesy of Dr. E. Myles Standish. Dr. Reed's ephemeris generating program, a list of minor planet elements, and the JPL planetary ephemeris are freeware which may be obtained from the author by sending a 100 Megabyte zip disk and stamped, addressed return mailer. They cannot be downloaded directly over the Internet.

Any objects whose brightest magnitudes near the time of MINOR PLANETS AT UNUSUALLY FAVORABLE maximum elongation vary by at least 2.0 in this interval and in ELONGATIONS IN 2006 2006 will be within 0.3 of the brightest occurring, or vary by at least 3.0 and in 2006 will be within 0.5 of the brightest occurring; Frederick Pilcher and which are visual magnitude 14.5 or brighter, are included. For Illinois College objects brighter than visual magnitude 13.5, which are within the Jacksonville, IL 62650 USA range of a large number of observers, these standards have been relaxed somewhat to include a larger number of objects. (Received: 5 October) Magnitudes have been computed from the updated magnitude parameters published in MPC28104-28116, on 1996 Nov. 25, or more recently in the Minor Planet Circulars. A list is presented of minor planets which are much brighter than usual at their 2006 apparitions. Close Oppositions may be in right ascension or in celestial longitude. approaches of five minor planets: , Here we use still a third representation, maximum elongation from 3103 Eger, (11405) 1999 CV3, (23817) 2000 PN9, and the Sun, instead of opposition. Though unconventional, it has the (68950) 2002 QF15, are the highlights of the year. advantage that many close approaches do not involve actual opposition to the Sun near the time of minimum distance and The minor planets in the lists which follow will be much brighter greatest brightness and are missed by an opposition-based at their 2006 apparitions than at their average distances at program. Other data are also provided according to the following maximum elongation. Many years may pass before these minor tabular listings: Minor planet number, date of maximum planets will be again as bright as in 2006. Observers are elongation from the Sun in format yyyy/mm/dd, maximum encouraged to give special attention to those which lie near the elongation in degrees, right ascension on date of maximum limit of their equipment. elongation, declination on date of maximum elongation, both in J2000 coordinates, date of minimum or brightest magnitude in Five small minor planets will make moderately to extremely close format yyyy/mm/dd, minimum magnitude, date of minimum approaches to Earth in calendar 2006 and are especially worthy of distance in format yyyy/mm/dd, and minimum distance in AU. observational scrutiny. 1980 Tezcatlipoca has a moderately close approach to 0.330 AU November 17. At magnitude 13.1 on Minor Planet Bulletin 33 (2006) 15

Users should note that when the maximum elongation is about Table 1 (continued) 177° or greater, the minimum magnitude is sharply peaked due to enhanced brightening near zero phase angle. Even as near as 10 Planet Max Elon D Max E RA Dec Min Mag D Mag Min Dist D Min Dist 1682 2006/09/05 177.2° 22h54m - 4° 2006/09/05 13.9 2006/09/03 0.805 days before or after minimum magnitude the magnitude is 1695 2006/10/27 177.0° 1h59m +15° 2006/10/27 14.3 2006/10/19 1.055 1756 2006/12/12 174.9° 5h12m +28° 2006/12/11 14.3 2006/12/04 1.101 generally about 0.4 greater. This effect takes place in greater time 1866 2006/05/18 118.8° 20h13m -47° 2006/06/06 13.8 2006/06/10 0.495 interval for smaller maximum elongations. There is some interest 1980 2006/12/05 161.7° 5h28m + 7° 2006/11/28 13.1 2006/11/17 0.330 2050 2006/06/03 179.2° 16h41m -21° 2006/06/03 13.4 2006/06/02 0.764 in very small minimum phase angles. For maximum elongations 2131 2006/08/06 160.3° 21h15m + 2° 2006/08/06 13.8 2006/08/07 0.704 E near 180° at Earth distance ∆, an approximate formula for the 2152 2006/11/13 171.7° 3h 1m +25° 2006/11/13 13.6 2006/11/10 1.477 2215 2006/12/03 179.8° 4h39m +22° 2006/12/03 13.8 2006/11/28 1.117 minimum phase angle φ is φ=(180°-E)/(∆+1). 2228 2006/12/04 177.0° 4h43m +19° 2006/12/04 14.1 2006/12/03 1.571 2274 2006/03/20 178.9° 11h55m - 0° 2006/03/20 13.4 2006/03/20 0.856 2348 2006/02/21 174.9° 10h 9m + 5° 2006/02/21 14.3 2006/02/18 1.041 2393 2006/07/29 163.7° 20h20m - 2° 2006/07/30 14.2 2006/08/01 1.673 2430 2006/11/01 173.2° 2h30m + 7° 2006/11/01 13.9 2006/10/26 0.951 2466 2006/08/30 179.4° 22h32m - 8° 2006/08/30 14.3 2006/08/31 1.210

Table 1. Numerical Sequence of Favorable Elongations 2501 2006/04/02 179.8° 12h46m - 5° 2006/04/02 13.8 2006/04/10 1.050 2569 2006/10/02 160.9° 1h 1m -14° 2006/10/03 14.0 2006/10/04 1.251 2580 2006/08/06 179.0° 21h 6m -17° 2006/08/06 14.1 2006/08/10 0.771 Planet Max Elon D Max E RA Dec Min Mag D Mag Min Dist D Min Dist 2651 2006/10/25 146.4° 2h48m -19° 2006/10/27 13.7 2006/10/27 1.107 2754 2006/09/19 166.5° 23h26m +11° 2006/09/20 14.5 2006/09/20 0.723 6 2006/08/05 176.9° 20h55m -14° 2006/08/05 7.8 2006/08/13 1.129 7 2006/11/15 174.4° 3h12m +23° 2006/11/14 6.8 2006/11/12 0.848 2834 2006/01/03 168.7° 6h51m +11° 2006/01/03 14.5 2006/01/06 1.198 10 2006/07/13 179.1° 19h27m -21° 2006/07/13 9.2 2006/07/09 1.874 2873 2006/06/17 176.7° 17h42m -20° 2006/06/17 14.3 2006/06/18 0.880 25 2006/09/30 157.1° 23h27m +20° 2006/09/25 10.0 2006/09/18 0.997 2950 2006/10/20 161.7° 2h 4m - 6° 2006/10/21 14.3 2006/10/23 1.092 44 2006/12/29 176.1° 6h31m +19° 2006/12/29 9.0 2006/12/31 1.092 3093 2006/07/04 178.5° 18h53m -21° 2006/07/04 14.0 2006/07/11 1.288 3103 2006/07/20 128.6° 22h59m + 5° 2006/08/01 13.2 2006/08/05 0.128 53 2006/01/25 177.0° 8h28m +15° 2006/01/25 10.9 2006/01/22 1.146 63 2006/05/01 170.4° 14h24m -24° 2006/05/03 9.9 2006/05/07 1.184 3127 2006/07/20 179.4° 19h57m -20° 2006/07/20 14.1 2006/07/24 1.102 68 2006/09/16 168.9° 23h51m -13° 2006/09/16 9.5 2006/09/14 1.272 3156 2006/03/11 172.0° 11h36m +11° 2006/03/11 14.3 2006/03/07 1.426 75 2006/08/30 175.7° 22h38m -13° 2006/08/30 10.2 2006/08/29 0.851 3197 2006/12/28 171.9° 6h24m +15° 2006/12/28 14.3 2006/12/25 1.249 77 2006/10/17 178.4° 1h24m +10° 2006/10/17 11.2 2006/10/19 1.380 3500 2006/08/07 179.5° 21h 7m -16° 2006/08/07 13.5 2006/08/08 0.791 3652 2006/06/20 178.1° 17h56m -21° 2006/06/20 14.5 2006/06/27 0.958 97 2006/12/23 158.7° 6h 0m + 2° 2006/12/21 9.9 2006/12/18 1.061 105 2006/03/30 179.1° 12h35m - 2° 2006/03/30 10.5 2006/04/06 1.085 3728 2006/02/09 159.4° 8h53m - 3° 2006/02/06 14.4 2006/02/03 1.265 111 2006/01/16 178.4° 7h51m +22° 2006/01/16 10.6 2006/01/16 1.350 3773 2006/09/28 177.4° 0h21m - 0° 2006/09/28 14.2 2006/09/24 0.774 177 2006/10/12 178.6° 1h 7m + 8° 2006/10/12 11.5 2006/10/12 1.116 3973 2006/08/03 176.5° 20h56m -20° 2006/08/03 14.3 2006/08/03 0.853 186 2006/09/17 170.3° 23h49m -11° 2006/09/16 10.9 2006/09/13 1.029 4155 2006/11/02 175.1° 2h26m +19° 2006/11/02 14.1 2006/10/27 0.892 4288 2006/10/06 165.6° 1h 2m - 8° 2006/10/05 14.3 2006/10/04 1.179 190 2006/01/10 172.0° 7h23m +14° 2006/01/10 12.3 2006/01/09 2.370 201 2006/07/28 174.5° 20h26m -13° 2006/07/29 10.9 2006/08/01 1.239 4335 2006/10/19 178.5° 1h39m + 8° 2006/10/19 14.4 2006/10/13 0.753 249 2006/08/21 177.7° 22h 4m -14° 2006/08/21 12.9 2006/08/28 0.966 4349 2006/12/03 173.2° 4h38m +15° 2006/12/02 14.1 2006/11/24 1.199 266 2006/12/01 174.6° 4h36m +16° 2006/12/01 11.8 2006/11/27 1.465 4420 2006/08/27 172.3° 22h13m - 2° 2006/08/26 13.7 2006/08/18 0.880 312 2006/05/07 170.0° 14h44m -26° 2006/05/07 11.9 2006/05/12 1.406 4428 2006/08/14 171.0° 21h50m -22° 2006/08/13 14.5 2006/08/08 0.823 5142 2006/10/20 179.5° 1h38m + 9° 2006/10/20 13.5 2006/10/21 0.855 323 2006/01/03 174.4° 7h 5m +28° 2006/01/02 11.6 2005/12/22 1.012 341 2006/08/07 167.3° 21h22m -28° 2006/08/07 11.8 2006/08/08 0.773 5199 2006/07/02 173.6° 18h44m -29° 2006/07/02 14.4 2006/07/02 1.141 353 2006/01/20 176.7° 8h13m +23° 2006/01/19 12.9 2006/01/08 1.057 5719 2006/08/11 179.5° 21h22m -15° 2006/08/11 14.4 2006/08/07 0.840 356 2006/11/09 167.9° 2h44m +28° 2006/11/10 10.6 2006/11/13 1.158 5764 2006/05/13 170.3° 15h33m - 9° 2006/05/14 14.4 2006/05/18 0.799 390 2006/01/05 172.6° 7h 7m +29° 2006/01/06 13.2 2006/01/08 1.368 6042 2006/12/15 176.9° 5h29m +20° 2006/12/14 14.2 2006/11/26 1.029 6260 2006/09/01 175.0° 22h34m - 3° 2006/09/01 14.4 2006/08/30 1.211 396 2006/06/27 178.0° 18h24m -21° 2006/06/27 12.4 2006/06/26 1.294 459 2006/10/09 175.2° 1h 3m + 1° 2006/10/09 12.6 2006/10/13 1.134 6425 2006/10/27 178.2° 2h 9m +11° 2006/10/27 13.9 2006/10/19 1.154 474 2006/08/17 174.4° 21h37m - 8° 2006/08/17 12.2 2006/08/15 0.926 6979 2006/09/29 176.4° 0h18m + 5° 2006/09/29 14.4 2006/09/23 1.101 477 2006/08/06 170.9° 21h15m -25° 2006/08/07 12.1 2006/08/09 0.970 7496 2006/12/05 168.8° 4h48m +11° 2006/12/04 14.4 2006/11/28 1.123 485 2006/01/17 156.3° 7h35m - 2° 2006/01/16 11.3 2006/01/15 1.299 11405 2006/08/17 166.6° 22h34m -20° 2006/08/10 12.5 2006/07/31 0.154 11574 2006/08/07 178.6° 21h 6m -15° 2006/08/07 14.4 2006/08/11 0.726 492 2006/07/31 177.4° 20h45m -20° 2006/07/31 13.1 2006/08/03 1.634 523 2006/01/04 177.2° 6h59m +19° 2006/01/04 12.5 2006/01/02 1.465 23187 2006/03/18 108.2° 11h 9m +72° 2006/03/07 12.0 2006/03/06 0.020 537 2006/07/08 175.5° 19h 4m -18° 2006/07/08 11.6 2006/07/11 1.370 68950 2006/06/04 127.3° 17h45m +28° 2006/05/19 14.3 2006/05/13 0.125 538 2006/10/13 171.1° 1h27m - 0° 2006/10/13 12.9 2006/10/11 1.663 543 2006/10/30 166.6° 1h58m +26° 2006/10/30 12.9 2006/10/30 1.617

554 2006/10/21 174.3° 1h33m +15° 2006/10/21 11.0 2006/10/24 1.065 571 2006/09/11 177.2° 23h21m - 7° 2006/09/11 13.0 2006/09/18 0.912 587 2006/02/23 169.5° 10h19m - 0° 2006/02/23 14.5 2006/02/23 0.963 606 2006/10/26 163.9° 1h40m +27° 2006/10/25 12.6 2006/10/22 1.058 Table 2. Temporal Sequence of Favorable Elongations 645 2006/01/18 170.3° 8h 8m +30° 2006/01/17 13.8 2006/01/15 1.795 Planet Max Elon D Max E RA Dec Min Mag D Mag Min Dist D Min Dist 646 2006/07/12 176.6° 19h26m -25° 2006/07/12 14.0 2006/07/20 0.935 685 2006/09/07 172.3° 22h49m + 0° 2006/09/06 13.1 2006/08/31 0.826 323 2006/01/03 174.4° 7h 5m +28° 2006/01/02 11.6 2005/12/22 1.012 704 2006/08/24 158.4° 21h45m + 9° 2006/08/25 10.0 2006/08/27 1.732 2834 2006/01/03 168.7° 6h51m +11° 2006/01/03 14.5 2006/01/06 1.198 717 2006/09/01 179.6° 22h43m - 8° 2006/09/01 13.8 2006/09/05 1.392 523 2006/01/04 177.2° 6h59m +19° 2006/01/04 12.5 2006/01/02 1.465 725 2006/11/17 178.2° 3h30m +17° 2006/11/17 13.6 2006/11/12 1.044 390 2006/01/05 172.6° 7h 7m +29° 2006/01/06 13.2 2006/01/08 1.368 190 2006/01/10 172.0° 7h23m +14° 2006/01/10 12.3 2006/01/09 2.370 748 2006/01/16 178.4° 7h51m +19° 2006/01/16 13.5 2006/01/14 2.276 756 2006/04/12 176.6° 13h18m -11° 2006/04/12 13.1 2006/04/14 1.729 111 2006/01/16 178.4° 7h51m +22° 2006/01/16 10.6 2006/01/16 1.350 758 2006/12/08 175.5° 4h59m +18° 2006/12/07 11.7 2006/12/06 1.730 748 2006/01/16 178.4° 7h51m +19° 2006/01/16 13.5 2006/01/14 2.276 760 2006/02/02 173.4° 9h10m +23° 2006/02/03 11.3 2006/02/08 1.568 485 2006/01/17 156.3° 7h35m - 2° 2006/01/16 11.3 2006/01/15 1.299 822 2006/12/21 178.7° 5h57m +22° 2006/12/21 13.5 2006/12/22 0.924 645 2006/01/18 170.3° 8h 8m +30° 2006/01/17 13.8 2006/01/15 1.795 353 2006/01/20 176.7° 8h13m +23° 2006/01/19 12.9 2006/01/08 1.057 826 2006/07/11 168.7° 19h15m -10° 2006/07/10 13.8 2006/07/07 1.187 880 2006/11/23 169.6° 3h40m +30° 2006/11/21 14.2 2006/11/12 1.282 53 2006/01/25 177.0° 8h28m +15° 2006/01/25 10.9 2006/01/22 1.146 882 2006/09/07 169.6° 22h46m + 3° 2006/09/08 13.6 2006/09/12 1.418 760 2006/02/02 173.4° 9h10m +23° 2006/02/03 11.3 2006/02/08 1.568 888 2006/12/05 160.2° 4h50m + 2° 2006/12/04 12.3 2006/12/03 1.234 1613 2006/02/03 178.2° 9h 9m +18° 2006/02/03 13.6 2006/01/27 1.173 895 2006/12/09 173.7° 4h57m +28° 2006/12/09 12.0 2006/12/09 1.752 3728 2006/02/09 159.4° 8h53m - 3° 2006/02/06 14.4 2006/02/03 1.265 2348 2006/02/21 174.9° 10h 9m + 5° 2006/02/21 14.3 2006/02/18 1.041 902 2006/09/19 179.2° 23h44m - 1° 2006/09/19 14.0 2006/09/21 1.034 916 2006/09/13 170.9° 23h15m + 4° 2006/09/13 12.5 2006/09/16 0.827 587 2006/02/23 169.5° 10h19m - 0° 2006/02/23 14.5 2006/02/23 0.963 947 2006/11/15 179.0° 3h19m +19° 2006/11/15 11.8 2006/11/09 1.111 1310 2006/03/02 165.7° 11h 1m +21° 2006/02/26 13.2 2006/02/15 0.891 968 2006/04/17 179.3° 13h39m -11° 2006/04/17 13.2 2006/04/14 1.629 3156 2006/03/11 172.0° 11h36m +11° 2006/03/11 14.3 2006/03/07 1.426 969 2006/11/06 175.9° 2h38m +19° 2006/11/05 14.3 2006/11/01 0.995 23187 2006/03/18 108.2° 11h 9m +72° 2006/03/07 12.0 2006/03/06 0.020 2274 2006/03/20 178.9° 11h55m - 0° 2006/03/20 13.4 2006/03/20 0.856 972 2006/09/24 165.8° 23h40m +13° 2006/09/24 12.5 2006/09/25 1.381 988 2006/10/13 178.9° 1h16m + 6° 2006/10/13 14.0 2006/10/12 1.420 105 2006/03/30 179.1° 12h35m - 2° 2006/03/30 10.5 2006/04/06 1.085 1089 2006/10/30 175.7° 2h24m + 9° 2006/10/30 13.2 2006/11/01 0.966 2501 2006/04/02 179.8° 12h46m - 5° 2006/04/02 13.8 2006/04/10 1.050 1187 2006/10/18 162.5° 1h 9m +26° 2006/10/19 13.7 2006/10/20 1.096 756 2006/04/12 176.6° 13h18m -11° 2006/04/12 13.1 2006/04/14 1.729 1242 2006/10/30 166.5° 2h 0m +26° 2006/10/30 12.8 2006/10/30 1.237 968 2006/04/17 179.3° 13h39m -11° 2006/04/17 13.2 2006/04/14 1.629 1281 2006/04/25 178.8° 14h14m -12° 2006/04/25 14.0 2006/05/04 1.252 1264 2006/06/11 159.1° 17h38m - 2° 2006/06/11 12.4 2006/06/12 1.436 1279 2006/06/19 168.5° 17h49m -34° 2006/06/19 14.0 2006/06/21 0.866 63 2006/05/01 170.4° 14h24m -24° 2006/05/03 9.9 2006/05/07 1.184 1281 2006/04/25 178.8° 14h14m -12° 2006/04/25 14.0 2006/05/04 1.252 1590 2006/05/02 179.1° 14h34m -15° 2006/05/02 13.3 2006/05/09 0.992 1283 2006/11/30 165.6° 4h33m + 7° 2006/11/29 13.8 2006/11/25 1.596 312 2006/05/07 170.0° 14h44m -26° 2006/05/07 11.9 2006/05/12 1.406 1310 2006/03/02 165.7° 11h 1m +21° 2006/02/26 13.2 2006/02/15 0.891 5764 2006/05/13 170.3° 15h33m - 9° 2006/05/14 14.4 2006/05/18 0.799 1866 2006/05/18 118.8° 20h13m -47° 2006/06/06 13.8 2006/06/10 0.495 1329 2006/08/15 175.0° 21h48m -18° 2006/08/15 13.3 2006/08/11 1.190 1369 2006/08/01 160.7° 20h22m + 0° 2006/08/01 14.0 2006/07/31 1.473 2050 2006/06/03 179.2° 16h41m -21° 2006/06/03 13.4 2006/06/02 0.764 1427 2006/09/13 163.1° 23h52m -19° 2006/09/11 13.5 2006/09/07 1.241 68950 2006/06/04 127.3° 17h45m +28° 2006/05/19 14.3 2006/05/13 0.125 1456 2006/08/12 169.6° 21h16m - 4° 2006/08/12 14.3 2006/08/15 1.575 1264 2006/06/11 159.1° 17h38m - 2° 2006/06/11 12.4 2006/06/12 1.436 1515 2006/11/08 178.4° 2h52m +15° 2006/11/08 14.2 2006/11/06 0.979 2873 2006/06/17 176.7° 17h42m -20° 2006/06/17 14.3 2006/06/18 0.880 1279 2006/06/19 168.5° 17h49m -34° 2006/06/19 14.0 2006/06/21 0.866 1545 2006/12/31 176.1° 6h43m +26° 2006/12/31 14.2 2007/01/06 1.228 1550 2006/11/15 175.9° 3h23m +14° 2006/11/14 13.0 2006/11/05 0.839 1590 2006/05/02 179.1° 14h34m -15° 2006/05/02 13.3 2006/05/09 0.992 1613 2006/02/03 178.2° 9h 9m +18° 2006/02/03 13.6 2006/01/27 1.173 1631 2006/08/25 167.5° 22h31m -22° 2006/08/25 13.4 2006/08/24 0.759 Minor Planet Bulletin 33 (2006) 16

Table 2 (continued) IMAGE SUBTRACTION PROCEDURE FOR OBSERVING FAINT ASTEROIDS Planet Max Elon D Max E RA Dec Min Mag D Mag Min Dist D Min Dist

3652 2006/06/20 178.1° 17h56m -21° 2006/06/20 14.5 2006/06/27 0.958 396 2006/06/27 178.0° 18h24m -21° 2006/06/27 12.4 2006/06/26 1.294 Bruce L. Gary and David Healy 5199 2006/07/02 173.6° 18h44m -29° 2006/07/02 14.4 2006/07/02 1.141 3093 2006/07/04 178.5° 18h53m -21° 2006/07/04 14.0 2006/07/11 1.288 5320 E. Calle Manzana 537 2006/07/08 175.5° 19h 4m -18° 2006/07/08 11.6 2006/07/11 1.370 Hereford, AZ 85615 826 2006/07/11 168.7° 19h15m -10° 2006/07/10 13.8 2006/07/07 1.187 [email protected] 646 2006/07/12 176.6° 19h26m -25° 2006/07/12 14.0 2006/07/20 0.935 10 2006/07/13 179.1° 19h27m -21° 2006/07/13 9.2 2006/07/09 1.874 3103 2006/07/20 128.6° 22h59m + 5° 2006/08/01 13.2 2006/08/05 0.128 3127 2006/07/20 179.4° 19h57m -20° 2006/07/20 14.1 2006/07/24 1.102 (Received: 5 October Revised: 8 October)

201 2006/07/28 174.5° 20h26m -13° 2006/07/29 10.9 2006/08/01 1.239 2393 2006/07/29 163.7° 20h20m - 2° 2006/07/30 14.2 2006/08/01 1.673 492 2006/07/31 177.4° 20h45m -20° 2006/07/31 13.1 2006/08/03 1.634 1369 2006/08/01 160.7° 20h22m + 0° 2006/08/01 14.0 2006/07/31 1.473 Main-belt asteroid 46053 was fainter than magnitude 20 3973 2006/08/03 176.5° 20h56m -20° 2006/08/03 14.3 2006/08/03 0.853 when lightcurve observations were made using an 6 2006/08/05 176.9° 20h55m -14° 2006/08/05 7.8 2006/08/13 1.129 477 2006/08/06 170.9° 21h15m -25° 2006/08/07 12.1 2006/08/09 0.970 amateur telescope and image analysis software 2131 2006/08/06 160.3° 21h15m + 2° 2006/08/06 13.8 2006/08/07 0.704 2580 2006/08/06 179.0° 21h 6m -17° 2006/08/06 14.1 2006/08/10 0.771 commonly used by amateurs. By subtracting images 341 2006/08/07 167.3° 21h22m -28° 2006/08/07 11.8 2006/08/08 0.773 taken more than an hour apart the background stars were 3500 2006/08/07 179.5° 21h 7m -16° 2006/08/07 13.5 2006/08/08 0.791 11574 2006/08/07 178.6° 21h 6m -15° 2006/08/07 14.4 2006/08/11 0.726 reduced to ~1% of their original intensity while 5719 2006/08/11 179.5° 21h22m -15° 2006/08/11 14.4 2006/08/07 0.840 preserving the asteroid at 100%. This method for dealing 1456 2006/08/12 169.6° 21h16m - 4° 2006/08/12 14.3 2006/08/15 1.575 4428 2006/08/14 171.0° 21h50m -22° 2006/08/13 14.5 2006/08/08 0.823 with interfering stars does not require the use of PSF- 1329 2006/08/15 175.0° 21h48m -18° 2006/08/15 13.3 2006/08/11 1.190 fitting and it is free of subjective artifacts associated 474 2006/08/17 174.4° 21h37m - 8° 2006/08/17 12.2 2006/08/15 0.926 11405 2006/08/17 166.6° 22h34m -20° 2006/08/10 12.5 2006/07/31 0.154 with pixel editing to remove nearby stars. Imperfect 249 2006/08/21 177.7° 22h 4m -14° 2006/08/21 12.9 2006/08/28 0.966 704 2006/08/24 158.4° 21h45m + 9° 2006/08/25 10.0 2006/08/27 1.732 matching of image pairs leads to residual systematic

1631 2006/08/25 167.5° 22h31m -22° 2006/08/25 13.4 2006/08/24 0.759 errors that vary during an observing session, but their 4420 2006/08/27 172.3° 22h13m - 2° 2006/08/26 13.7 2006/08/18 0.880 75 2006/08/30 175.7° 22h38m -13° 2006/08/30 10.2 2006/08/29 0.851 fast-changing nature does not seriously impair the 2466 2006/08/30 179.4° 22h32m - 8° 2006/08/30 14.3 2006/08/31 1.210 717 2006/09/01 179.6° 22h43m - 8° 2006/09/01 13.8 2006/09/05 1.392 derivation of rotation light curves.

6260 2006/09/01 175.0° 22h34m - 3° 2006/09/01 14.4 2006/08/30 1.211 1682 2006/09/05 177.2° 22h54m - 4° 2006/09/05 13.9 2006/09/03 0.805 685 2006/09/07 172.3° 22h49m + 0° 2006/09/06 13.1 2006/08/31 0.826 882 2006/09/07 169.6° 22h46m + 3° 2006/09/08 13.6 2006/09/12 1.418 Asteroid 46053 Davidpatterson is a faint main-belt object 571 2006/09/11 177.2° 23h21m - 7° 2006/09/11 13.0 2006/09/18 0.912 discovered in 2001 by one of the authors (DH) using the Junk 916 2006/09/13 170.9° 23h15m + 4° 2006/09/13 12.5 2006/09/16 0.827 1427 2006/09/13 163.1° 23h52m -19° 2006/09/11 13.5 2006/09/07 1.241 Bond Observatory 20-inch Ritchey-Chretien telescope. At the time 68 2006/09/16 168.9° 23h51m -13° 2006/09/16 9.5 2006/09/14 1.272 of the two observing sessions described here the asteroid was 186 2006/09/17 170.3° 23h49m -11° 2006/09/16 10.9 2006/09/13 1.029 902 2006/09/19 179.2° 23h44m - 1° 2006/09/19 14.0 2006/09/21 1.034 predicted to be fainter than magnitude 19.7 and its location was 2754 2006/09/19 166.5° 23h26m +11° 2006/09/20 14.5 2006/09/20 0.723 only ~21 degrees from the galactic center. The asteroid’s highest 972 2006/09/24 165.8° 23h40m +13° 2006/09/24 12.5 2006/09/25 1.381 3773 2006/09/28 177.4° 0h21m - 0° 2006/09/28 14.2 2006/09/24 0.774 elevation angle from our observing site was 34 degrees. 6979 2006/09/29 176.4° 0h18m + 5° 2006/09/29 14.4 2006/09/23 1.101 25 2006/09/30 157.1° 23h27m +20° 2006/09/25 10.0 2006/09/18 0.997

2569 2006/10/02 160.9° 1h 1m -14° 2006/10/03 14.0 2006/10/04 1.251 Amateurs usually do not attempt to measure rotation light curves 4288 2006/10/06 165.6° 1h 2m - 8° 2006/10/05 14.3 2006/10/04 1.179 459 2006/10/09 175.2° 1h 3m + 1° 2006/10/09 12.6 2006/10/13 1.134 for asteroids this faint, this close to the galactic center and at such 177 2006/10/12 178.6° 1h 7m + 8° 2006/10/12 11.5 2006/10/12 1.116 538 2006/10/13 171.1° 1h27m - 0° 2006/10/13 12.9 2006/10/11 1.663 low elevations (where seeing is degraded), partly because it is customary to use PSF-fitting programs for faint objects in 988 2006/10/13 178.9° 1h16m + 6° 2006/10/13 14.0 2006/10/12 1.420 77 2006/10/17 178.4° 1h24m +10° 2006/10/17 11.2 2006/10/19 1.380 crowded star fields, and few amateurs have the necessary 1187 2006/10/18 162.5° 1h 9m +26° 2006/10/19 13.7 2006/10/20 1.096 4335 2006/10/19 178.5° 1h39m + 8° 2006/10/19 14.4 2006/10/13 0.753 programs (such as IRAF). This was an opportunity for evaluating 2950 2006/10/20 161.7° 2h 4m - 6° 2006/10/21 14.3 2006/10/23 1.092 an image subtraction procedure using general-purpose software. 5142 2006/10/20 179.5° 1h38m + 9° 2006/10/20 13.5 2006/10/21 0.855 554 2006/10/21 174.3° 1h33m +15° 2006/10/21 11.0 2006/10/24 1.065 2651 2006/10/25 146.4° 2h48m -19° 2006/10/27 13.7 2006/10/27 1.107 606 2006/10/26 163.9° 1h40m +27° 2006/10/25 12.6 2006/10/22 1.058 Observations 1695 2006/10/27 177.0° 1h59m +15° 2006/10/27 14.3 2006/10/19 1.055 6425 2006/10/27 178.2° 2h 9m +11° 2006/10/27 13.9 2006/10/19 1.154 Asteroid 46053 was ~1.65 a.u. from Earth during the two 543 2006/10/30 166.6° 1h58m +26° 2006/10/30 12.9 2006/10/30 1.617 1089 2006/10/30 175.7° 2h24m + 9° 2006/10/30 13.2 2006/11/01 0.966 observing dates, 2005.09.01 and 2005.09.26, and its magnitude 1242 2006/10/30 166.5° 2h 0m +26° 2006/10/30 12.8 2006/10/30 1.237 2430 2006/11/01 173.2° 2h30m + 7° 2006/11/01 13.9 2006/10/26 0.951 was predicted to be 19.7 and 20.1 (H = 16.2). The asteroid’s

4155 2006/11/02 175.1° 2h26m +19° 2006/11/02 14.1 2006/10/27 0.892 galactic coordinates were latitude -17 degrees, longitude +13, so 969 2006/11/06 175.9° 2h38m +19° 2006/11/05 14.3 2006/11/01 0.995 1515 2006/11/08 178.4° 2h52m +15° 2006/11/08 14.2 2006/11/06 0.979 there were more background stars than usual. Air ranged 356 2006/11/09 167.9° 2h44m +28° 2006/11/10 10.6 2006/11/13 1.158 2152 2006/11/13 171.7° 3h 1m +25° 2006/11/13 13.6 2006/11/10 1.477 from 1.8 to 3.4 and the seeing was poor (5.0 to 6.5 “arc FWHM).

7 2006/11/15 174.4° 3h12m +23° 2006/11/14 6.8 2006/11/12 0.848 947 2006/11/15 179.0° 3h19m +19° 2006/11/15 11.8 2006/11/09 1.111 A 32-inch fork-mounted Ritchey-Chretien telescope (OGS brand) 1550 2006/11/15 175.9° 3h23m +14° 2006/11/14 13.0 2006/11/05 0.839 725 2006/11/17 178.2° 3h30m +17° 2006/11/17 13.6 2006/11/12 1.044 was used with a SBIG STL-6303E CCD camera. Junk Bond 880 2006/11/23 169.6° 3h40m +30° 2006/11/21 14.2 2006/11/12 1.282 Observatory (MPC code 701) is located at 4425 feet altitude near 1283 2006/11/30 165.6° 4h33m + 7° 2006/11/29 13.8 2006/11/25 1.596 266 2006/12/01 174.6° 4h36m +16° 2006/12/01 11.8 2006/11/27 1.465 Sierra Vista, AZ. Each observing date consisted of ~3 hours of 2215 2006/12/03 179.8° 4h39m +22° 2006/12/03 13.8 2006/11/28 1.117 4349 2006/12/03 173.2° 4h38m +15° 2006/12/02 14.1 2006/11/24 1.199 clear-filter asteroid imaging using MaxIm DL; exposure times 2228 2006/12/04 177.0° 4h43m +19° 2006/12/04 14.1 2006/12/03 1.571 were either 2 or 4 minutes (unguided). All-sky photometry 888 2006/12/05 160.2° 4h50m + 2° 2006/12/04 12.3 2006/12/03 1.234 1980 2006/12/05 161.7° 5h28m + 7° 2006/11/28 13.1 2006/11/17 0.330 observations of Henden or Skiff catalog star fields were used to 7496 2006/12/05 168.8° 4h48m +11° 2006/12/04 14.4 2006/11/28 1.123 758 2006/12/08 175.5° 4h59m +18° 2006/12/07 11.7 2006/12/06 1.730 establish telescope photometry constants. Image analysis was done 895 2006/12/09 173.7° 4h57m +28° 2006/12/09 12.0 2006/12/09 1.752 using only MaxIm DL. 1756 2006/12/12 174.9° 5h12m +28° 2006/12/11 14.3 2006/12/04 1.101 6042 2006/12/15 176.9° 5h29m +20° 2006/12/14 14.2 2006/11/26 1.029 822 2006/12/21 178.7° 5h57m +22° 2006/12/21 13.5 2006/12/22 0.924 Author BLG has employed judicious pixel editing to remove stars 97 2006/12/23 158.7° 6h 0m + 2° 2006/12/21 9.9 2006/12/18 1.061 3197 2006/12/28 171.9° 6h24m +15° 2006/12/28 14.3 2006/12/25 1.249 in the sky background annulus, for example; this is a practice that

44 2006/12/29 176.1° 6h31m +19° 2006/12/29 9.0 2006/12/31 1.092 should rightly produce shudders of concern. The following image 1545 2006/12/31 176.1° 6h43m +26° 2006/12/31 14.2 2007/01/06 1.228

Minor Planet Bulletin 33 (2006) 17 subtraction procedure is an objective alternative for removing Figure 1 shows a 4-image average before the subtraction process. most of the effect of interfering stars. Figure 2 shows a “signal subtracted image.” The asteroid is easily visible in the subtracted image. The sky reference annulus in Fig. Image Subtraction Analysis 2 is clear of interfering background stars, whereas the Fig. 1 image has several stars within the sky reference annulus. The measured Each raw image was calibrated using master dark and flat field fluxes for background stars in the signal subtracted image are images. During a 3-hour observing session the asteroid’s apparent typically 1% of the values in the unsubtracted image. Since no motion was many times the FWHM of star images. This allowed rescaling (or smoothing or sharpening) has been performed on the for the creation of a “reference image” using several images when signal image during the subtraction process the asteroid is present the asteroid was far from its location in a “signal image.” Since with 100% of its original flux. many images were used to create a reference image its subtraction from a signal image led to a “subtracted image” having a noise level similar to that of the signal image. Before subtraction the FWHM of the two images were checked for a match, and if they differed the reference image was either sharpened or smoothed to achieve a match. The flux (i.e, intensity) of a specific star was checked for equality, and the reference image was rescaled (during the subtraction process) to achieve a star flux match.

Figure 3. Rotation lightcurves for observing dates 2005.09.01 (filled diamonds) and 2005.09.26 (open circles). SE bars are stochastic (SE mag = 1.1/SNR). The time axis is 2005.09.01 UT hours, with 236 rotation periods subtracted from the 2005.09.26 data. The dashed sinusoid has a period of 5.0523 hours and an Figure 1. Signal image before subtraction showing asteroid amplitude of 0.40 magnitude. (CV=20.0). FOV = 7.2 x 4.7 ’arc. The two stars to the upper-right of the sky background annulus have CV = 16.2. The asteroid’s average brightness faded 0.27 magnitude between the two observing dates, which is slightly less than the expected 0.47 magnitude fade. The 0.20 magnitude difference could be due to photometric calibration errors, or to the fact that the asteroid was observed from different perspectives and G differs from 0.15. Although we suggest a provisional H-value revision of +0.3 magnitude (H = 16.5) this is uncertain because the asteroid’s color is not known. We adopted a typical asteroid color V-Rc = +0.40 (Binzel, 2005); if V-Rc were actually +0.00, for example, the H- value solution would be 0.3 magnitude brighter (i.e., H=16.2) based on the telescope system’s clear filter sensitivity to star color (as determined from Landolt stars).

Although it is not our objective to report the asteroid’s period, amplitude or H value, it should be noted that when there are only two observing sessions separated by 25 days there will be an ambiguity of rotation period solutions, such that, in this, case P = 5.05232 + N * 0.01075 where N = -5 to +5, etc. Figure 2. Subtracted image. Top circle is the “offset alignment dot.” The 3-circle photometry pattern is centered on the asteroid. Ghost Artifact Systematic Errors The most tedious part of this process is image alignment. For the The error bars in Fig. 3 are stochastic only. Clearly, some of the observations reported here the asteroid moved a significant data differ from the “model fit” by statistically significant fraction of a FWHM distance between images. This meant that amounts. This cannot be due to shortcomings of the model since images could not be stacked using the star field. This, and other the timescale for the appearance of these large offsets have a considerations, led to a sequence of manipulations that are timescale much shorter than the rotation period. It is far more described at the following web site: http://brucegary.net/ist/ Only likely that these large departures are due to shortcomings of the an overview of the image subtraction concepts are described here. image subtraction process. For example, “ghost artifacts” from an imperfect subtraction (due to unequal FWHM or unequal intensity Minor Planet Bulletin 33 (2006) 18 after rescaling) are more likely to show up in the sky background fast objects the time order of magnitude between consecutive scan, annulus than the signal circle simply due to the difference in pixel of the same sky region, is one hour. area of these two regions. When these artifacts are in the sky background annulus they may reduce the asteroid’s apparent However, as seen from Earth, all the bodies are liable brightness, whereas when they appear in the signal aperture they to a period of very low angular rate. Normally the bodies move may make the asteroid appear brighter. The brightenings may be eastward (direct motion) but, sometimes, the motion reverses to less frequent but they can produce larger errors. Consider also the the opposite direction, or retrograde. During the motion inversion case of an asteroid becoming fainter (due to rotation or changing from direct to retrograde (and vice versa) the angular rate is near observing date); faint and bright asteroids moving through similar zero (stationary points), making it difficult to detect the star fields will exhibit different levels of systematic errors due to displacement on different CCD images taken one hour apart. It star ghosts. This may account for the one very low datum in Fig. 3 will be better to compare different images taken one day apart. when the asteroid was faintest. Based on the appearance of Fig. 3 we estimate that when an asteroid as faint as 46053 is moving Thus, the detection of new asteroids near stationary points is a job though a crowded star field (~21 degrees from the galactic center) more suited for an amateur astronomer, that has more time to the ghost artifacts due to incomplete star subtraction produce a devote to the same sky region. Moreover, with a low angular rate, component of varying systematic error of ~0.15 magnitude. it is possible to observe objects more faint than usually. Due to However, as also can be seen from Fig. 3, these ghost artifacts “opposition effect”, the apparent luminosity of a stationary come and go with a period of ~1/2 hour, which in this case is asteroid is lower than during the opposition but in this period the comparable to the time it takes the asteroid to move a distance of angular rate reach the maximum and the detection is very easy on ~3*FWHM. Therefore, the image subtraction is unlikely to an interval time of few minutes. Such objects are readily found by seriously impair the task of establishing an asteroid’s rotation light professional surveys so, from an amateur standpoint, it is more curve. probable the discovery of new stationary asteroids.

Conclusion The Asteroids Stationary Points

It is possible to perform image subtraction for the purpose of The most interesting solar system regions to explore for new establishing rotation lightcurves of faint asteroids using standard, objects are the main , with distances of 2.2 - 3.3 AU Windows-based astronomical image analysis programs, such as from the Sun (Lewis, 1997) and the Edgeworth-, with MaxIm DL. Considering the many user-commanded procedures distances of 30 – 50 AU from the Sun (Morbidelli et al., 2003). required in this analysis it is not known whether a program or Suppose an asteroid on a heliocentric circular orbit on the script could be written that would perform most of the image plane (Figure 1). Where are the stationary points on the geocentric subtraction tasks. We do not anticipate widespread enthusiasm for celestial sphere? If Δ(t) is the Earth-asteroid vector at time t, and such a labor-intensive procedure. Nevertheless, this report Δ(t + dt) is the same vector at time t+dt, when the asteroid is demonstrates that amateurs are capable of measuring rotation light curves for faint asteroids in crowded star fields with a commonly- stationary the two vectors must stay parallel. With this condition used Window-based astronomical image processing program such we can calculate the geocentric position of stationary points on the as MaxIm DL. ecliptic. If λE and λ A are the Earth and asteroid heliocentric longitude, the radius vectors will be: References (1) rE = rE (cos(λE )x + sin(λE )y) Binzel, R. P. (2005). Personal communication. (2) rA = rA (cos(λA )x + sin(λA )y)

IN SEARCH OF STATIONARY ASTEROIDS In the preceding formulae, x and y are the vectors, while rE and r are the orbital rays of the Earth and asteroid. Considering that Albino Carbognani A (Figure 1), we can obtain the Earth-asteroid vector: Physics Department, Parma University (Italy) rE + Δ = rA [email protected] (3) Δ(t)= (rA cos(λA )− rE cos(λE ))x + (rA sin(λA )− rE sin(λE ))y (Received: 1 October)

If we divide Eqn (3) by rE , all the distance are measured in AU,

Modern asteroid surveys are optimized for the discovery we can replace rA with r. Now, if in (3) we replace t with t+dt and of new fast moving objects, but the angular rate of an perform a Taylor series development to the first order we have: asteroid can be very low when the body is observed near the geocentric stationary points. This paper is an (4) Δ(t + dt)= Δ(t)+ (sin(λE )dλE − r sin(λA )dλA )x + (r cos(λA )dλA − cos(λE )dλE )y introduction to the search for new asteroids on the ecliptic near the most probable stationary points. The two vectors Δ(t) and Δ(t + dt) are parallel if their vectorial cross product is zero: Nowadays there are several operating near-Earth objects (NEO) surveys. The goal is to perform a complete inventory of Earth- Δ t × Δ t + dt = 0 (5) crossing objects. The modern surveys are specialized to detect ( ) ( ) moving objects with high angular rate. For automatic search of

Minor Planet Bulletin 33 (2006) 19

It can be verified that the preceding formula is true if the night. Comparing the subsequent scan will be possible to following relation is satisfied: discovery new objects with very low proper motion.

2 References r ω A +ωE (6) cos(λE − λA )= r(ω A +ωE ) Morbidelli, A., Brown, M.E., and Levison, H.F. (2003). “The Kuiper Belt and its Primordial Sculpting”. Earth, Moon and

Here ω A and ωE are the asteroid and Earth heliocentric orbital Planets 92, 1-27. angular velocity. When this condition is satisfied the asteroid is stationary if observed from Earth. Now we can know the Earth- Lewis, J. S. (1997). Physics and Chemistry of the Solar System. asteroid distance when the asteroid is stationary: Academic Press, CA

2 (7) Δ = 1+ r − 2r cos(λE − λA )

In this formula r and Δ are in AU. From (6) and (7) it follows that the angular distance, measured on the ecliptic, between the stationary point and the current opposition point (the point on the ecliptic opposite to the Sun) is:

r (8) sin(α )= sin(λE − λA ) Δ

The α value can be positive or negative. With (8) we can identify the two stationary points on the ecliptic. Equations (6), (7) and (8) are applicable also in the case of a circular orbit inside the Earth orbit. In this case α is the asteroid geocentric solar elongation.

The distribution of asteroids inside the main asteroid belt is uneven, they seem to avoid some areas known as the Kirkwood gaps. The greatest asteroid concentrations are near 1.9, 2.4, 2.6 Figure1: Adopted geometry for the Sun-Earth-asteroid system. and 3.10 AU from the Sun. The outcome of this situation is that the stationary points where new discoveries are most probable are at ±48°, ±52°, ±54° and ±57° on the ecliptic from the current opposition point. For the Trans-Neptunian Objects (TNOs), the greatest object concentrations are at 39 and 44 AU, so the stationary points are at ±81° and ±82° from the current opposition point (Table I, Figure 2).

During the stationary phase a residual contribution to the asteroid angular rate is given by the parallax due to Earth rotation that can shift the observer by a quantity comparable to Earth’s diameter. For main-belt objects the residual mean velocity is between 1.3 and 0.6 arcsec/hour while for TNOs down to zero (about 0.4 arcsec/hour). This “parallax angular rate” is at minimum during stationary point rising and setting and reach the maximum value at local meridian transit. These residual angular rates are low if compared with angular rate during opposition (from 46 to 31 arcsec/hour for a main-belt body), and don’t change the substance of the preceding results. Another residual contribution to angular rate may come from the orbit inclination on the ecliptic. Figure 2: Stationary points vs. heliocentric distance. Fortunately most asteroids orbits are near the ecliptic plane. r (AU) ωA (°/day) Δ (AU) α (°) The search strategy (days)

The search strategy for new low angular motion objects is similar 1.90 972 0.3705 1.10 ±48 to the search for new fast moving objects (i.e. with sky regions 2.40 1358 0.2651 1.66 ±52 comparison), with the important difference that the interval time 2.60 1531 0.2351 1.88 ±54 between two consecutive scan is measured in days instead in 3.10 1994 0.1805 2.44 ±57 hours. Of course the best sky region to explore are on the ecliptic 39.0 88958 4.05·10-3 38.8 ±81 near the stationary points given in Table I. For a given night, 44.0 106603 3.38·10-3 43.8 ±82 thanks to the time available, it is possible to scan large sky region around stationary points, and putting together many CCD images Table I: Stationary points for the greatest asteroids concentration with a long exposition time. The same thing can be repeated next of the asteroid main belt and Kuiper belts.

Minor Planet Bulletin 33 (2006) 20

ANALYSIS OF THE LIGHTCURVE OF 1992 UY4 gives the phase angle for the date in Column 1. Columns 3 and 4 give the Phase Angle Bisector (PAB) longitude and latitude. Brian D. Warner

Palmer Divide Observatory Date Phase LPAB BPAB 17995 Bakers Farm Rd. 2005 Jul 12 5.0 289.9 -3.4 Colorado Springs, CO 80908 USA 2005 Jul 17 5.0 293.3 -3.0 [email protected] 2005 Aug 3 14.0 318.3 +1.5 Cristovao Jacques, Eduardo Pimentel Table 1. The phase and Phase Angle Bisector values for CEAMIG-REA Observatory observations of 1992 UY4. Minas Gerais, BRAZIL Results. Behrend measured the images from Stoss et al. and then Greg Crawford forwarded the data (JD/magnitude pairs) to Warner, who at the Bagnall Beach Observatory same time sent the Crawford/Jacques data to Behrend. This Salamander Bay, AUSTRALIA resulted in parallel data sets containing data from all observers. Warner and Behrend did independent period analysis based on the Raoul Behrend, Alain Klotz combined data set. Updates following the arrival of new data were Geneva Observatory given frequently to Dr. Benner for planning purposes. Sauverny, SWITZERLAND

Reiner Stoss, Jaime Nomen, Salvador Sanchez Observatorio Astronomico de Mallorca Mallorca, SPAIN

(Received: 6 October)

Photometric observations of the near-Earth asteroid

1992 UY4 were made in 2005 July in support of planned radar observations. Analysis of the resulting data showed a synodic period of 12.912±0.005h and a lightcurve amplitude of 0.26±0.02m. Including additional data obtained in early 2005 August yields a more precise synodic period of 12.9060±0.0008h.

In early 2005 July, Dr. Lance Benner of NASA/JPL issued a request to the Minor Planet Mailing List for astrometric and photometric observations of the near-Earth asteroid (NEA) 1992 Figure 1. The lightcurve of 1992 UY4 using data obtained during UY4 in support of planned radar observations. Since the lightcurve the 2005 July-August campaign. parameters of the asteroid were not known at that time, photometry was important in order to determine if radar Nearly 1130 data points all observers obtained by all observers in observations would be possible, the spin rate having a 2005 were used for the pre-radar observations period analysis. considerable effect on the Doppler width of the returned signal. Warner, using MPO Canopus, derived a synodic period of 12.912±0.004h and an amplitude of 0.26±0.02m. Behrend, using Jacques in Brazil was among those who responded, using his other software, found a period of 12.955±0.007h. When the 0.30m SCT and ST-7XME equipment to obtain images on 2005 August data from the Behrend group became available, they were July 13-17. Crawford also took up the request and obtained images merged with the data from July, making for a data set of more than at his Australian observatory on 2005 July 12-15 using a 0.28m 1300 points. Analysis of this data set yielded a more precise SCT and ST-9XE. Jacques was not able measure his images at the period of 12.9060±0.0008h (Warner and Behrend). This value time and so made them available to Warner, who used MPO differs from the July-only solution by only slightly more than the Canopus to perform aperture photometry on the images to obtain uncertainty of that solution. The amplitude of the curve did not data for lightcurve analysis. Crawford also used MPO Canopus to change. Figure 1 shows the lightcurve using the data from both measure his images and then sent the resulting data to Warner. July and August. Note from Table 1 that the phase and PAB Also joining in the observing effort were Stoss, Nomen, and values for the short range in July are very similar. However, by the Sanchez, who used a 0.30m SCT and SBIG STL-1001E camera first of August, the phase angle had increased by nearly 9° while located on Mallorca and operated remotely from Germany. the PAB longitude increased nearly 25°. The change in period is Approximately 80 observations were made over the period of slightly more than 1-sigma of the reported errors. However, given 2005 July 13-16. Another 173 observations were made on 2005 the relatively large changes in phase angle and PAB values, it’s August 3. The latter were after the radar observations had been possible that the change is real, i.e., due to an actual change in the made but the data were important in that they helped refine the synodic period. If so, then it may prove to be valuable information period. in future analysis involving the spin axis and shape of the asteroid.

Table 1 shows the important observation details covering the During July, before the radar observations, the analysis was range of dates over which observations were made. Column 2 dominated by the preponderance of data from Australia and Brazil. Usually, having two stations well removed in longitude is a

Minor Planet Bulletin 33 (2006) 21 benefit when an asteroid has a period of nearly 12 hours. In this THE ENIGMATIC LIGHTCURVE FOR THE case, however, the stations in Australia and Brazil, were about 11 HUNGARIA ASTEROID 5641 MCCLEESE hours apart, which meant the observations afforded only a 10% overlap and so nearly repeated coverage of the curve. Fortunately Brian D. Warner the number of observations and ability of each station to cover a Palmer Divide Observatory significant portion of a cycle overcame this potential difficulty. 17995 Bakers Farm Rd. Colorado Springs, CO 80908 USA In early August, Dr. Benner reported his group had successfully [email protected] observed 1992 UY4 and that the efforts of this collaboration had proven invaluable in making that possible (Benner, private Petr Pravec, Peter Kusˇnirák communication). The full results of the analysis of the radar data Astronomical Institute will be published once the analysis is completed. The TAROT Ondrˇejov, Czech Republic automated telescope (Boer 1999) observed 1992 UY4 in V and R bands on 2005-08-05 (phase angle around 24°). Reference stars Adrian Galad, Leos Kornos were extracted from the Tycho-2 catalog (Hog et al., 2000) and Modra Observatory their V were computed from the statistical relation between V and Bratislava, Slovakia (Bt, Vt) (Hog et al, op. cit.). Stars fainter than V~10.5 were Donald P. Pray rejected to avoid the known photometric defect at the faint end of Carbuncle Hill Observatory the Tycho-2. Stars with experimental color indexes V-R too far Coventry, RI USA from the one of the asteroid were also rejected. V magnitudes were computed using the remaining reference stars and their V-R Walter Cooney, Jr., John Gross, Dirk Terrell color index measured from a subset of V and Sonoita Research Observatory R-filtered images. V magnitudes were than included in the Sonoita, AZ USA lightcurve; the difference between these observations and the "mean" value from the ephemeredes (assuming G=0.15) and the Shannon Nudds rotational ephemeredes from the lightcurve, permitted a correction Elginfield Observatory to the H absolute photometric value. We find H=17.71, and London, ON Canada estimate V-R=0.32. One must note that the reduction scheme (Behrend, 2001) used implicitly H defined as the temporal mean Russ Durkee magnitude of the computed lightcurve, not the magnitude Shed of Science Observatory corresponding to the temporal mean flux; in the present case, the Minneapolis, MN USA difference between these two definitions is nevertheless smaller than 0.01 mag. (Received: 8 October)

Summary. This study shows the benefits of building professional- amateur collaborations. Within a short time of the initial call for Photometric observations of the Hungaria member observations from Dr. Benner on the Minor Planet Mailing List asteroid 5641 McCleese were made from May to July (http://groups.yahoo.com/group/mpml/), several amateurs joined 2005. The lightcurve showed unusual characteristics that forces to provide vital data to the professional community. Its made a final solution difficult. A part of the data fit with hoped that studies like this will encourage amateurs and a synodic period of 7.268±0.001h (or 14.54h±0.01h) professionals alike to work together on future projects. with an amplitude of 0.04±0.01m. However, some data showed very different behavior, having more rapid References variations and larger amplitudes up to 0.13m. So far, there are no explanations for the anomalies. We discuss Behrend R. (2001). Orion 304, 12. two possible interpretations, tumbling and asynchronous binary, but neither seems to fit well with the data. Bringer, M., Boer, M., Peignot, C., Fontan, G., and Merce, C (1999). “The TAROT observatory data management”. A&AS 138, 581. Warner made initial observations of 5641 McCleese at the Palmer Divide Observatory in mid-May 2005. After a few sessions, the Hog, E., Fabricius, C., Makarov, V.V., Urban, S., Corbin, T., behavior of the asteroid was considered unusual and Pravec was Wycoff, G., Bastian, U., Schwekendiek, P., and Wicenec, A., contacted for his advice and analysis. It was decided to make a call (2000). A&A 355, L28 for observations to members of Pravec’s Binary Asteroids group, which consists of observers located around the world. Over the next few weeks, more than two thousand observations were submitted to Pravec and Warner to see if a solution could be found. Table I shows the details of the equipment used in the survey. The goal was to keep observational errors to 0.02m or less by using sufficient aperture and/or exposures. The viewing aspect did not change significantly during the range of dates, which might have explained some of the anomalies. From May to July 2005, the phase angle bisector longitude ranged from 233 to 248 degrees while the latitude ranged from 37 to 30 degrees.

Minor Planet Bulletin 33 (2006) 22

Observer Scope / Camera Dates the full data set is used do not completely exclude the longer Warner 0.50m / FLI-1001E 15 period as a valid solution. Figures 3 and 4 show the full data sets Pravec et al 0.65m / AP-7p 1 phased to 7.268h and 14.548h respectively, again being the best Galad et al 0.60m / AP-8 6 fits found by MPO Canopus. The legends are not displayed since Pray 0.35m / ST-10XME 2 more than 30 separate sessions are involved in the data set that Cooney et al 0.35m / STL-1001E 1 includes more then 2100 observations. Durkee 0.35m / ST-10XE 2 Nudds 1.20m / Custom 5 In summary, the lightcurve of 5641 McCleese during mid-2005 was found to be highly complex with no satisfactory solution Table I. Observer and equipment details. found. The data set of more than 2100 observations somewhat favored a period of 7.268±0.001h, but alternate solutions were Unfortunately, as more data became available, the solution found as well. So far, no definitive model has been proposed that became more elusive, exhibiting behavior that Pravec had never would account for the curve’s behavior. Observations at future seen before. Many images were remeasured and some data points apparitions, especially those with significantly different viewing removed as a result but the net effect was the same: no unique aspects may help provide a final solution. solution with a reasonable interpretation could be found. A part of the data can be fitted with a synodic period of 7.267±0.001h (see Acknowledgements Figures 1 and 3) or 14.54±0.01h (see Figures 2 and 4). However, as seen in all the figures, some data showed rapid variations with The work at Ondrˇejov was supported by the Grant Agency of the amplitudes up to 0.13m. Czech Republic, Grant 205/05/0604. The work at Modra was supported by the Slovak Grant Agency for Science VEGA, Grant At one point during the analysis, Pravec considered the possibility 1/0204/03 and by The Planetary Society Gene Shoemaker NEO that the curve was the result of two nearby frequencies. In this Grant. case, the lightcurve parts of higher amplitude would be where the two components superposed constructively, while the low- References amplitude parts would be a destructive superposition. The curve would be complicated by the fact that neither of the two Harris, A.W., Young, J.W., Bowell, E., Martin, L.J., Millis, R.L., components would be a simple sinusoidal wave, but rather had a Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne, signal in a few harmonics. That possibility remains but there is no H., and Zeigler, K.W. (1989). “Photoelectric Observations of definitive evidence for it either. Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186.

The observations made at Ondrˇejov Observatory used the Rc filter Pravec, P., Harris, A.W., Scheirich, P., Kusnirak, P., Sarounova, and were calibrated to an absolute scale. Assuming a value of G = L., Hergenrother, C.W., Mottola, S., Hicks, M.D., Masi, G., 0.15±0.2, the derived HR = 14.0±0.3. Assuming a V-R value of Krugly, Yu.N., Shevchenko, V.G., Nolan, M.C., Howell, E.S., 0.4, this would give HV = 14.4. This is considerably fainter than Kaasalainen, M., Galad, A., Brown, P., DeGraff, D.R., Lambert, the current listing in the MPCORB file of HV = 12.7. Assuming an J.V., Cooney Jr., W.R., and Foglia, S. (2005). “Tumbling albedo of pv = 0.3±0.1 (typical for the Hungaria class), the Asteroids”. Icarus 173, 108-131. estimated mean diameter of the asteroid is 3.2±0.8km, where the error includes both the uncertainty in H and the range of pv. Pravec and 56 co-authors (2005a). “Photometric Survey of Binary Near-Earth Asteroids”. Icarus, submitted. Two possible interpretations of the anomalous behavior were considered: tumbling and binary. None of them fits well with the data, though neither can be ruled out with certainty. The tumbling asteroid hypothesis is not supported as we have not resolved a truly two-periodic behavior expected for excited rotators. A damping time scale of excited rotation for a 3-km sized asteroid is estimated to be on the order of 10-100 Myr for periods of 7-15 hours, the range suggested by the data. In this case, the asteroid might be in a state of excited rotation if it is relatively young or more rigid than the average population (see Pravec 2005 and references within). The asynchronous hypothesis is not supported as we have neither an additive two-periodic behavior nor mutual attenuation events as in other binaries (Pravec et al., 2005a). Future calibrated observations at a different geometry of the asteroid are needed for this enigmatic asteroid.

Figure 1 shows a reduced data set, using only that from the Palmer Divide Observatory obtained in May and early June, phased to the approximate period of 7.27h. The three anomalous variations in the curve, i.e., excessive brightness, were confirmed by Figure 1. The lightcurve of 5641 McCleese using data obtained in remeasuring the images. Durkee observed at least one similar May through early June 2005 by Warner. The data have been event, though it was not as strong. phased to a period of 7.27h, or about 0.002h longer than the period derived using the full data set. Figure 2 shows the same data set phased to the double period of 14.65h, the best fit for that data alone. While it does not fit the usually assumed bimodal form, there are aspects to it that when Minor Planet Bulletin 33 (2006) 23

ANALYSIS OF THE LIGHTCURVE FOR 6249 JENNIFER

Brian D. Warner Palmer Divide Observatory 17995 Bakers Farm Rd. Colorado Springs, CO 80908 [email protected]

John Gross Sonoita Research Observatory Tucson, AZ

Alan W. Harris Space Science Institute La Canada, CA 91011

(Received: 11 August Revised: 29 October)

Figure 2. The same data as used in Figure 1 have been phased to In 2002, the second author (Gross) observed the an alternate period solution of 14.65h, which is the best fit for this Hungaria group member, 6249 Jennifer, and derived a subset of the data. synodic period based on a bimodal curve of 4.950±0.003h with a 0.45±0.03 mag. amplitude. In mid- 2005, the first author (Warner) observed the same asteroid and confirms the result with a 4.9535±0.0009h period and 0.14±0.02 mag. amplitude, based on a monomodal curve, likely indicating the 2005 apparition being nearly pole-on.

The Palmer Divide Observatory consists of three telescopes, one 0.5-m Ritchey-Chretien and two 0.35-m SCT telescopes. For this asteroid, the 0.5m scope was used with a Finger Lakes Instrumentation CCD (1001E) chip running at –30°C. Exposures were 120s. The Sonoita Research Observatory used a 0.35m SCT and an SBIG ST9E CCD camera operating at f/7.

The table below shows the important observation details. Column 3 gives the phase angle for the mid-date for each set of observations. Columns 4 and 5 give the Phase Angle Bisector (PAB) longitude and latitude respectively, also for the mid-point of each of the data sets. Figure 3. The complete data set, involving more than 2100 observations, was used to generate this plot phased to the period of

7.268h. Obs Date Phase LPAB BPAB Gross 2002 Jun 17-22 19.0 254.7 26.4 Warner 2005 Jul 12-28 35.0 346.0 36.3

The data from 2002, originally measured in MPO Canopus, were no longer available and had to be reconstructed from a plot made at the time of the observations. This was done by using a program that converted the X/Y coordinates on the plot to phase and magnitude. A separate file was created for each date. The phase values were then converted to Julian Date by using the JD of the 0% phase from the original plot and accounting for the number of rotations based on a period of 4.957h. The converted data set was imported into MPO Canopus where Fourier analysis (Harris 1989) could be performed. Figure 1 shows the regenerated lightcurve from that procedure. Assuming a bimodal curve and using the reconstructed data, the synodic period was found to be 4.950±0.003h with an amplitude of 0.45±0.03m.

The 2005 data were obtained by measuring images taken at the Palmer Divide Observatory using aperture photometry in MPO Figure 4. The complete data set phased to the alternate period Canopus. There again, period analysis was performed on the data solution of 14.548h. and a synodic period of 4.9535±0.0009 found, but only when a Minor Planet Bulletin 33 (2006) 24 monomodal curve was assumed, i.e., having only one minimum and maximum per cycle. The amplitude of the curve was 0.14±0.02m. Figure 2 is a composite lightcurve of the 2005 data.

The low amplitude of the 2005 lightcurve compared to 2002 suggests that the aspect in 2005 was likely close to pole-on. This aspect, along with the rather large phase angle, could also explain the dominance of the first harmonic in the monomodal lightcurve. The nearly 90° difference in the PAB would therefore imply that the 2002 aspect was nearly equatorial, consistent with the larger amplitude and more ordinary bimodal lightcurve form.

Additional observations are planned through late 2005, which should provide lightcurves at phase angles down to 20°, or near that of the 2002 apparition, and another 30° change in the PAB longitude. It’s hoped that the additional lightcurves will provide additional insight into the possibilities for the asteroid’s shape and spin axis orientation as well as looking for any hint that the asteroid might be binary. Figure 2. The lightcurve of 6249 Jennifer using data obtained in 2005 by B.D. Warner. The data are phased against a period of References 4.9535h. Harris, A.W., Young, J.W., Bowell, E., Martin, L.J., Millis, R.L., Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne, H., and Zeigler, K.W. (1989). “Photoelectric Observations of THE LIGHTCURVE FOR THE Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186. HUNGARIA ASTEROID 4232 APARICIO

Brian D. Warner Palmer Divide Observatory 17995 Bakers Farm Rd. Colorado Springs, CO 80908 USA [email protected]

Petr Pravec, Peter Kusˇnirák Astronomical Institute Ondrˇejov, Czech Republic

Zuzana Kanˇuchová, Marek Husárik Skalnaté Pleso Observatory Tatranská Lomnica, Slovak Republic

David Higgins Hunters Hill Observatory Ngunnawal, Canberra Australia

(Received: 8 October)

Figure 1. The lightcurve of 6249 Jennifer using reconstructed data Photometric observations of 4232 Aparicio, a member obtained in 2002 June by J. Gross. The data are phased against a of the Hungaria class, were made from late August to period of 4.950h. First and last data points each night are indicated late September 2005. The majority of the data revealed a by circles or boxes, respectively, around the points. likely synodic period of 54.4±0.1h and amplitude of 0.82±0.02m. However, a small subset of the data do not fit with this solution. Given the approximate size and period of the object, there remains the possibility that it may have non-principal axis rotation, i.e., it is a tumbler.

Warner made initial observations of 4232 Aparicio in late August 2005. It became quickly apparent that the lightcurve had at least a long period and possibly some unusual characteristics. Warner contacted Pravec and, at his recommendation, Husárik (who turned the project over to Kanˇuchová) and Higgins. This allowed having observations from points widely separated in longitude and so the possibility for having extended runs on a given day. The basic equipment data for each observatory is given in Table I.

Minor Planet Bulletin 33 (2006) 25

Over the interval of observations, the longitude of the phase angle might have a slow, low-amplitude secondary period that was bisector remained near 357 degrees, while the latitude changed indicative of NPA rotation. However, the current data set does not only from 7.1 to 1.9 degrees. Thus very little change occurred in provide enough evidence to include or exclude this possibility the observing aspect. with certainty.

Observer Scope / Camera Dates Observations by Kusˇnirák at Ondrˇejov using the Rc filter allowed

Warner 0.35m / FLI-1001E 11 finding an HR = 13.44±0.14, assuming G = 0.15±0.2. If a typical Pravec et al 0.60m / AP-8 1 value of V-R = 0.4 is applied, this gives HV = 13.84, which Kanˇuchová 0.61m / ST-8XME 3 compares to a value of 13.5 in the MPCORB data table. Assuming Higgins 0.35m / ST-8E 1 an albedo of pv = 0.3±0.1 (typical for the Hungaria class), the estimated mean diameter of the asteroid is 4.1±0.9km, where the

Table I. Observer and equipment details. Note that Warner used a error includes both the uncertainty in H and the range of pv. 0.5m instrument for the last two of his sessions. Based on this size and rotation rate, the estimated damping time Most the measurements of the image were done using MPO out of excited rotation is approximately 2 Gy, or about one-half Canopus, written by Warner. This program uses aperture the age of the solar system (Pravec et al, 2005). If the asteroid has photometry and allows merging of data from several observers a rigidity similar to the average population, it’s reasonable to into a common data set. Period analysis at PDO was also done expect that the dampening has not been completed and, therefore, with Canopus, which incorporates the Fourier analysis algorithm a small element of NPA rotation might be found. developed by Harris (1989). Pravec used a program that he wrote to conduct his independent period analysis. This program includes Acknowledgements additional features that allow resolution of complex curves such as those of binary and tumbling asteroids. The work at Ondřejov was supported by the Grant Agency of the Czech Republic, Grant 205/05/0604 Only two of the sessions used in the subset of all available data covered to be what appeared to be a maximum. No session The work at Skalnaté Pleso Observatory was supported by VEGA: actually covered an apparent minimum. This, combined with the the Slovak Grant Agency for Science (grant No. 4012). fact that most of the data were not calibrated, complicated the analysis to some degree. However, since some sessions in References combination others with provided nearly continuous coverage over Harris, A.W., Young, J.W., Bowell, E., Martin, L.J., Millis, R.L., a prolonged period, this helped narrow the possibilities for the Poutanen, M., Scaltriti, F., Zappala, V., Schober, H.J., Debehogne, placement of the sessions within the lightcurve. Still, minor H., and Zeigler, K.W. (1989). “Photoelectric Observations of displacements of individual sessions do alter the solution, but only Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186. on the order of a few tenths of an hour and so not a significant portion of the assumed period. Pravec, P., Harris, A.W., Scheirich, P., Kusnirak, P., Sarounova, L., Hergenrother, C.W., Mottola, S., Hicks, M.D., Masi, G., Using those sessions for that could be merged into a reasonable Krugly, Yu.N., Shevchenko, V.G., Nolan, M.C., Howell, E.S., lightcurve, the synodic period was found to be 54.4±0.1h and the Kaasalainen, M., Galad, A., Brown, P., DeGraff, D.R., Lambert, amplitude 0.82±0.02m. See Figure 1. J.V., Cooney Jr., W.R., and Foglia, S. (2005). “Tumbling Asteroids”. Icarus 173, 108-131.

Figure 1. The lightcurve of 4232 Aparicio. The plot is the result of a subset using all but two sessions and is phased to a period of 54.4h.

The two unused sessions could not be fit into the curve using any reasonable period. This lead to the consideration that the asteroid Minor Planet Bulletin 33 (2006) 26

LIGHTCURVE ANALYSIS OF ASTEROIDS synodic period of 11.977±0.001h, with a lightcurve amplitude of 2139 MAKARADZE AND 5580 SHARIDAKE 0.34m. 452 images taken in ten sessions between September 3 and September 24, 2005 were used. With a period of nearly 12h, the Donald P. Pray period of rotation would have been extremely difficult or Carbuncle Hill Observatory impossible to determine from a single site. The collaboration with P.O. Box 946 Modra observatory is a perfect example of how cooperation Coventry, RI 02816, USA between widely separated sites is highly desirable. [email protected] 5580 Sharidake. A member of the , Endate and Adrián Galád, Štefan Gajdosˇ, Leosˇ Kornosˇ and Jozef Világi Watanabe discovered 5580 Sharidake in 1988 at Kitami. IRAS Modra Observatory V4.0 lists an “H” of 13.2. Eight observing sessions were Bratislava, Slovakia performed between September 25, and October 1, 2005. 295 images were taken to derive a synodic period of 14.580±0.005h, Marek Husarik and amplitude of 0.39m. The phase angle ranged 7.3 - 15.0 deg. Skalnaté Pleso Observatory Tatranská Lomnica, Slovakia Acknowledgements

Peter Kusnirak Reasearch at Modra was supported by VEGA, the Slovak Grant Ondrejov Observatory Agency for Science Grant 1/0204/03, and by The Planetary Ondrejov, Czech Republic Society Gene Shoemaker NEO Grant. Research at Skalnaté Pleso Observatory was supported by a grant from VEGA, the Slovak (Received: 6 October) Grant Agency for Science (grant No. 4012). Thanks are given to Brian Warner for his continued development and improvement of Lightcurve period and amplitude results are reported for the program, “Canopus”, and to Petr Pravec for his general help two asteroids observed at Carbuncle Hill Observatory, and encouragement in the field of asteroid research. Modra Observatory, Skalnaté Pleso Observatory, and Ondrejov Observatory during September - October References 2005: 2139 Makaradze, 11.977±0.001h, 0.34m; 5580 Sharidake, 14.580±0.005h, 0.39m. IRAS V4.0 from NASA Small Bodies Node of the Planetary Data System, IRAS Minor Planet Survey V4.0. Observations at Carbuncle Hill Observatory were made using two http://pdssbn.astro.umd.edu/nodehtml/sbdb.html telescope/CCD systems housed in separate buildings. One was a SBIG ST-10XME CCD camera, binned 3x3, coupled to a 0.35m Pravec, P. (2005). Photometric Survey of Asynchronous Binary f/6.5 SCT. The other consisted of a SBIG ST-7ME CCD camera, Asteroids , http://www.asu.cas.cz/~asteroid/binastphotsurvey.htm. binned 1x1, coupled to a 0.25m f/4 Schmidt-Newtonian. These systems produced image dimensions of 21x14 arc min (1.9 arcsec per pixel), and 23x16 arc min (1.8 arcsec per pixel), respectively. All observations were taken through the “clear” filter. Skalnaté Pleso Observatory used a 0.65-m f/4.2 Newtonian reflector and a SBIG ST-8XME CCD camera. Frames were binned 2x2 (1.4 arcsec per pixel). The system produced image dimensions of 19x13 arcminutes. Differential photometry was performed through a Johnson-Cousins R filter. Modra Observatory used a 0.6m, f/5.5 reflector with an AP8p CCD camera. Image dimensions were 25 arcmin squared (1.5 arcsec per pixel). All images were taken through the “clear” filter. Ondrejov Observatory used a 0.65m, f/3.6 telescope with an Apogee AP7p CCD, and an R filter designed to closely match the Cousins system.

Both objects were targets listed by Pravec of Ondrejov Observatory in his search for asynchronous binary asteroids (Pravec 2005). All images were calibrated via dark frames, bias frames and flat field frames. Lightcurve construction and analysis was accomplished using “Canopus” developed by Brian Warner. Data submitted by the co-authors was combined and integrated into the period solutions also using “Canopus”. Differential photometry was used in all cases, and all measurements were corrected for light travel time. In our results, neither object showed any indication of being a binary system.

2139 Makharadze. This asteroid was discovered on June 30, 1970 at Nauchnyj by T. Smirnova. It is a member of the , and has an “H” value of 12.8, as listed by the IRAS Minor Planet Survey, Small Bodies Node of NASA’s Planetary Data System, (henceforth IRAS V4.0) It was observed at phase angles ranging from 7.4-5.5 degrees. Makharadze was determined to have a Minor Planet Bulletin 33 (2006) 27

LIGHTCURVE PHOTOMETRY OPPORTUNITIES larger upload sites such as OLAF, SAPC, and the ADU. For more JANUARY – MARCH 2006 information about those sites, please contact Warner at the email address given above. Brian D. Warner Palmer Divide Observatory Lightcurve Opportunities 17995 Bakers Farm Rd. Colorado Springs, CO 80908 Brightest Harris Data # Name Date Mag Dec U Period Amp. ------Mikko Kaasalainen 2834 Christy Carol 1 03.8 14.5 +12 0 Rolf Nevanlinna Institute 1 03.1 13.0 +26 2 7.385 0.14 2222 Lermontov 1 03.8 14.6 +23 0 P.O. Box 68 (Gustaf Hallstromin katu 2b, room A422) 2444 Lederle 1 06.3 14.5 +23 0 FIN-00014 University of Helsinki 1720 Niels 1 06.7 14.7 +22 0 Finland 1435 Garlena 1 06.1 14.6 +15 0 2085 Henan 1 13.0 14.5 +21 1 32. 0.5 1 15.1 12.6 +19 2 8.824 0.11 Alan W. Harris 2067 Aksnes 1 16.0 14.9 +19 2 17.75 0.24 Space Science Institute 1 16.1 10.6 +23 2 22.2 0.1 645 Agrippina 1 17.9 13.7 +30 2 32.6 0.18 4603 Orange Knoll Ave. 1717 Arlon 1 20.9 14.5 +28 0 La Canada, CA 91011-3364 2455 Somville 1 20.2 14.8 +20 0 1888 Zu Chong-Zhi 1 21.0 14.0 +11 0 Petr Pravec 85804 1998 WQ5 1 21.7 15.0 -12 0 3458 Boduognat 1 24.0 14.7 +17 0 Astronomical Institute 1238 Predappia 1 25.8 14.9 +38 0 CZ-25165 Ondrejov 1 25.7 10.9 +16 2 17. >0.1 Czech Republic 2 01.2 14.3 +27 1 64. 0.19 2762 Fowler 2 01.0 14.7 +16 0 [email protected] 7895 Kaseda 2 02.9 14.4 +17 0 2737 Kotka 2 03.0 14.7 +23 0 We present here three lists of “targets of opportunity” for the 2 03.1 13.8 +26 2 8.19 0.31 3816 Chugainov 2 05.3 14.4 +14 0 period 2006 January through March. The first list is those 3728 IRAS 2 07.0 14.3 - 4 2 8.19 0.31 asteroids reaching a favorable apparition during this period, are 561 Ingwelde 2 13.8 14.9 +13 0 <15m at brightest, and have either no or poorly constrained 2862 Vavilov 2 13.0 14.5 + 7 0 2288 Karolinum 2 15.7 14.5 +34 0 lightcurve parameters. These circumstances make the asteroids 3260 Vizbor 2 15.6 14.6 + 3 0 particularly good targets for those with modest “backyard” 4718 Araki 2 16.6 14.5 +14 0 telescopes, i.e., 0.2-0.5m. 1999 Hirayama 2 20.3 14.1 +12 0 2535 Hameenlinna 2 21.9 14.4 + 8 0 2348 Michkovitch 2 21.1 14.2 + 6 0 The goal for these asteroids is to find a well-determined rotation 2 22.6 11.8 +12 2 9.44 0.20 rate, if at all possible. Don’t hesitate to solicit help from other 5750 Kandatai 2 23.7 15.0 + 9 0 2094 Magnitka 2 24.1 13.9 + 2 0 observers at widely spread longitudes should the initial finding for 802 Epyaxa 2 24.2 14.5 +15 0 the period indicate that it will be difficult for a single station to 3141 Buchar 2 27.7 15.0 + 4 0 find the period. This could be for the fact that the period has a 2846 Ylppo 3 08.7 15.0 +11 0 1969 Alain 3 09.0 15.0 + 2 0 multiple almost exactly equal to the interval between observing 3156 Ellington 3 11.1 14.3 +11 1 >15. >0.15 runs or the period is long, i.e., 18 hours to several days. 7360 Moberg 3 12.1 14.8 - 3 0 616 Elly 3 13.1 13.6 + 5 2 5.301 0.34 19651 1999 RC112 3 14.9 14.8 + 1 0 The Low Phase Angle list includes asteroids that reach very low 3 15.7 14.0 - 2 2 14.586 0.24 phase angles. Getting accurate, calibrated measurements (usually 8213 1995 FE 3 19.1 14.8 + 9 0 V band) at or very near the day of opposition can provide 4580 Child 3 19.4 14.5 + 4 2 4.181 0.24 400 Ducrosa 3 19.5 13.9 - 7 2 6.87 0.62 important information for those studying the “opposition effect”, 2274 Ehrsson 3 20.0 13.3 - 1 0 which is when objects near opposition brighten more than simple 2181 Fogelin 3 22.8 14.9 + 5 0 geometry would predict. 3 24.6 12.7 + 0 2 18. 0.1 105 Artemis 3 30.3 10.4 - 3 2 16.84 0.15

With current methods under common use, it’s required to get Low Phase Angle Opportunities several lightcurves spread from different apparitions in order to derive a model of the asteroid shape and pole orientation. The # Name Date PhA V Dec ------final list is those asteroids needing only a small number of 01 02.4 0.36 12.5 -22 lightcurves to allow Kaasalainen and others to work on a shape 01 04.2 0.25 11.4 -22 model. It should be noted that many of the asteroids have been on 01 06.0 0.12 6.2 +23 01 09.9 0.20 13.6 -22 the list for some time, so work on them is strongly encouraged in 566 Stereoskopia 01 14.1 0.62 13.9 -23 order to “clear the decks”. When getting data for shape modeling, 466 Tisiphone 01 15.0 0.54 12.7 +19 it’s strongly recommended that you do absolute photometry, 338 Budrosa 01 15.6 0.21 13.9 -20 111 Ate 01 16.1 0.64 10.6 +23 meaning that the observations are not differential but absolute 01 19.1 0.89 12.5 -18 values put onto a standard system, such as Johnson V. If this is not 1653 Yakhontovia 01 23.7 0.18 14.0 +20 possible or practical, accurate relative photometry is also 01 26.0 0.59 12.7 -18 129 Antigone 01 27.1 0.59 11.8 -17 permissible. This is where all differential values are against a 212 Medea 01 27.5 0.27 12.2 +19 calibrated zero point that is not necessarily on a standard system. 01 28.6 0.19 13.7 -18 02 03.2 0.76 12.4 +15 1613 Smiley 02 03.5 0.82 13.6 +18 We encourage anyone doing lightcurve work to publish their 02 07.7 0.82 13.9 -17 results in the Minor Planet Bulletin and, if nothing else, make the 206 Hersilia 02 08.2 0.11 13.9 -15 data available on a personal website. Previous issues have covered 02 10.1 0.42 13.6 -16 Minor Planet Bulletin 33 (2006) 28 Low Phase Angle Opportunities (continued) THE MINOR PLANET BULLETIN (ISSN 1052-8091) is the quarterly journal of the Minor Planets Section of the Association of Lunar and # Name Date PhA V Dec Planetary Observers – ALPO. Beginning with volume 32, the current and ------most recent issues of the MPB are available on line, free of charge at 1384 Kniertje 02 17.8 0.60 12.7 +11 http://www.minorplanetobserver.com/mpb/default.htm . Subscription 02 18.6 0.85 13.6 -09 02 21.8 0.44 12.4 -11 information for conventional printed copies is given below. 174 Phaedra 02 22.9 0.70 12.3 +08 356 Liguria 02 23.5 0.77 13.3 -12 Nonmembers are invited to join ALPO by communicating with: Matthew 203 Pompeja 02 26.4 0.17 13.8 -09 L. Will, A.L.P.O. Membership Secretary, P.O. Box 13456, Springfield, IL 388 Charybdis 03 01.3 0.41 13.8 -09 62791-3456 ([email protected]). The Minor Planets Section is 03 05.5 0.72 14.0 -08 directed by its Coordinator, Prof. Frederick Pilcher, Department of 03 05.6 0.59 13.4 -07 03 06.9 0.56 12.3 -07 Physics, Illinois College, Jacksonville, IL 62650 USA 03 07.2 0.09 13.9 +05 ([email protected]), assisted by Lawrence Garrett, 206 River Road, 03 08.0 0.46 12.3 -06 Fairfax, VT 05454 USA ([email protected]). , 1587 Kahrstedt 03 10.4 0.81 14.0 +06 7630 Conrad St., Zephyrhills, FL 33544-2729 USA (qho@bitnik. com) is 616 Elly 03 13.1 0.73 13.7 +05 Associate Coordinator for Observation of NEO’s, and Steve Larson, Lunar 03 13.4 0.13 13.7 +03 03 14.3 0.31 13.3 -02 and Planetary Laboratory, 1629 E. University Blvd., University of 48 Doris 03 18.2 0.18 12.4 -01 Arizona, Tucson, AZ 85721 USA ([email protected]) is Scientific 03 19.3 0.60 12.4 -01 Advisor. The Asteroid Photometry Coordinator is Brian D. Warner, 2274 Ehrsson 03 20.0 0.49 13.4 -01 Palmer Divide Observatory, 17995 Bakers Farm Rd., Colorado Springs, 03 24.2 0.46 13.6 +00 CO 80908 USA ([email protected]). 482 Petrina 03 24.5 0.55 12.7 +00 635 Vundtia 03 26.1 0.15 13.5 -02 105 Artemis 03 30.2 0.41 10.5 -03 The Minor Planet Bulletin is edited by Dr. Richard P. Binzel, MIT 54-410, Cambridge, MA 02139 USA ([email protected]), produced by Dr. Robert A. Shape/Spin Modeling Opportunities Werner, JPL MS 301-150, 4800 Oak Grove Drive, Pasadena, CA 91109 USA (robert.a.werner@jpl..gov), and distributed by Derald D. Nye. Brightest Per # Name Date Mag Dec (h) Amp. U The contact for all subscriptions, contributions, address changes, etc. is: ------ 1 01. 12.6 +32 5.982 0.04-0.10 4 Mr. Derald D. Nye 165 Loreley 1 01. 12.5 +32 7.226 0.12-0.15 2 Minor Planet Bulletin 1 01. 13.1 +24 10.77 0.17 3 1 01. 12.0 -11 9.763 0.11 3 10385 East Observatory Drive 1 09.0 13.0 +16 3.968 0.29-0.71 4 Corona de Tucson, AZ 85641-2309 USA 47 Aglaja 1 18.9 12.3 +27 13.20 0.03-0.17 4 ([email protected]) 1 29.4 12.5 -02 8.630 0.12 3 (Telephone: 520-762-5504) 1 31.7 10.6 +10 5.978 0.05-0.24 4 2 04.8 11.0 +19 9.402 0.08-0.13 4 Annual subscription rates for the Minor Planet Bulletin by postal delivery: 2 05.8 10.7 +19 29.43 0.07 3 3 08.8 9.8 +11 8.910 0.15-0.36 4 238 Hypatia 3 19.3 12.3 -01 8.86 0.12-0.15 4 Payment Payment by 3 20.8 11.7 -08 14.030 0.1 -0.40 3 by check credit card 3 21.9 12.2 -05 14.845 0.19-0.24 3 North America $14.00 $15.00 3 27.8 12.8 +10 8.1789 0.23 3 All other $19.00 $20.00

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Minor Planet Bulletin 33 (2006)