Apr-Jun, 31-2 - MinorPlanet.Info
Transcription
Apr-Jun, 31-2 - MinorPlanet.Info
29 THE MINOR PLANET BULLETIN BULLETIN OF THE MINOR PLANETS SECTION OF THE ASSOCIATION OF LUNAR AND PLANETARY OBSERVERS VOLUME 31, NUMBER 2, A.D. 2004 APRIL-JUNE 29. CCD OBSERVATIONS AND PERIOD DETERMINATION OF FIFTEEN MINOR PLANETS photometric R (red) filter, although some observations required a C (clear glass) filter for an improved signal-to-noise ratio. Kevin Ivarsen Sarah Willis Laura Ingleby Dan Matthews Melanie Simet In general we selected asteroids that did not have periods listed in an October 2003 revision of the list of Harris (2003) and that would be near opposition at the time of observation. At the beginning of this project, eleven of the asteroids had undetermined periods. However, by the project’s completion asteroids 1645 Waterfield and 228 Agathe were being studied by other astronomers as posted on the CALL website (http://www.minorplanetobserver.com/astlc/default.htm). Monson (2004) presents a preliminary period determination for 1645 Waterfield that agrees with our data. No result for 228 had been released at the time this paper was reviewed. Department of Physics and Astronomy Van Allen Hall University of Iowa Iowa City, IA 52242 kevin-ivarsen@uiowa.edu (Received: 17 November Revised: 15 February) We have determined the periods of fifteen minor planets using differential photometry. Eleven of these minor planets had unknown periods, one had an uncertain period, and three had well-known periods. We observed a minimum of two epochs for each object in order to construct composite lightcurves. The periods ranged from 3.7 to 15.2 hours. The objects we report results for are: 174 Phaedra, 228 Agathe, 342 Endymion, 354 Eleonora, 365 Corduba, 373 Melusina, 575 Renate, 1084 Tamariwa, 1171 Rusthawelia, 1388 Aphrodite, 1501 Baade, 1544 Vinterhanseni, 1645 Waterfield, 1799 Koussevitzky, and 2097 Galle. We observed several minor planets from September 27 to October 21, 2003 using the Rigel Telescope (MPC Code 857; see http://phobos.physics.uiowa.edu/tech/rigel.html) at the Winer Observatory near Sonoita, Arizona (31° 39’ N 110° 37’ W). The Rigel Telescope is a robotic facility operated remotely by faculty and students at the University of Iowa for research and educational use. We chose a site in Arizona because of the favorable seeing conditions (2.5 to 3.5 arcsecond FWHM) and the number of clear nights per year. The telescope is scheduled nightly and controlled over the Internet. The telescope is a 37 cm f/14 classical Cassegrain with a 16-bit CCD camera. The camera is an FLI IMG-1024 with a backside illuminated CCD sensor. In this telescope configuration the camera has an image scale of 1 arcsecond per pixel. A signal to noise estimate for 30-second exposures is shown in Figure 1. Most of the images were taken using a Johnson-Cousins To ensure the quality and accuracy of our experimental method, we observed four asteroids with existing entries in the Harris list and confirmed their periods. These asteroids are 174 Phaedra, 354 Eleonora, 575 Renate, and 1084 Tamariwa. Asteroid 1084 Tamariwa previously had two reported periods of 6.153 hours and 7.08 hours. Our initial period estimate matched the 7.08 hour result, although this resulted in a very noisy combined lightcurve. Further analysis revealed 6.19 hours as being a much better result. We believe that the 7.08 hour period estimate can be discounted with a high level of confidence. Information about each epoch of observation is displayed in Table I. Our results are summarized in Table II, and our lightcurves are shown in the Appendix. Additional information and data for all of our observations may be obtained from our website, http://phobos.physics.uiowa.edu/research/asteroids. Our results may also be found on the CALL website. We thank Alan Harris for his careful review of the first draft of this paper. References Harris, A. W. (2003). http://cfa-www.harvard.edu/iau/lists/Light curveDat.html Monson, A. (2004). http://krypton.mnsu.edu/~monsoa1/welcome_files/Asteroid.htm EDITOR’S NOTE: The team of Ivarsen et al. are to be congratulated for their prolific results accomplished using a robotic telescope at a distant favorable location. Their results clearly demonstrate the highly productive capabilities of such systems for asteroid lightcurve work. Minor Planet Bulletin 31 (2004) 30 Table I – Observation details Table II – Asteroid rotation results Ast# 174 174 174 174 174 228 228 228 342 342 342 342 354 354 354 354 354 365 365 365 373 373 373 373 575 575 575 1084 1084 1084 1084 1171 1171 1388 1388 1388 1388 1388 1388 1501 1501 1501 1544 1544 1544 1544 1544 1645 1645 1799 1799 1799 1799 2097 2097 2097 2097 P.A.B. Ast. Long. Lat. P.A. Range 174* 8 +10 4.0- 7.3 228 18 +4 3.8- 6.5 342 21 +5 2.8- 3.3 354* 352 -13 7.6-12.3 365 359 +1 2.3-11.1 373 0 0 2.5- 9.3 575* 359. +4 3.4- 4.4 1084* 20 -1 0.6- 1.7 1171 26 -4 1.9- 2.0 1388 7 -10 4.5- 8.1 1501 21 +1 0.6- 1.5 1544 9 -3 6.2- 9.3 1645 15 +1 3.4- 3.8 1799 9 -8 3.6- 7.4 2097 9 +5 2.8- 7.5 01 11 15 16 17 16 17 21 13 14 16 19 01 13 14 16 19 27 28 16 29 13 14 15 27 28 29 12 13 14 17 19 20 01 02 13 14 15 19 14 15 17 13 14 15 16 19 16 17 01 02 16 17 30 11 15 17 Epoch Filter Exposure #Images Mag Oct 03 R 15 84 13.0 Oct 03 R 30 38 12.8 Oct 03 R 30 49 12.8 Oct 03 R 30 38 12.5 Oct 03 R 30 54 12.5 Oct 03 R 30 39 13.5 Oct 03 R 30 60 13.4 Oct 03 R 30 38 13.6 Oct 03 R 30 62 12.6 Oct 03 R 30 62 12.5 Oct 03 R 15 27 12.8 Oct 03 R 30 58 12.8 Oct 03 R 30 37 11.0 Oct 03 R 30 38 11.5 Oct 03 R 30 35 11.4 Oct 03 R 15 14 11.5 Oct 03 R 30 32 11.7 Sep 03 C 15 133 12.8 Sep 03 R 30 56 12.3 Oct 03 R 30 42 12.6 Sep 03 R 15 68 13.6 Oct 03 R 15 23 14.0 Oct 03 R 15 16 13.6 Oct 03 R 15 44 13.9 Sep 03 C 15 131 13.7 Sep 03 R 30 54 13.8 Sep 03 R 30 69 14.1 Oct 03 R 15 10 14.1 Oct 03 R 15 10 13.9 Oct 03 R 15 43 13.5 Oct 03 R 15 67 14.1 Oct 03 R 15 84 13.4 Oct 03 R 15 41 13.0 Oct 03 R 15 36 15.3 Oct 03 R 30 31 15.4 Oct 03 R 30 44 15.4 Oct 03 R 30 47 15.6 Oct 03 R 15 34 15.8 Oct 03 R 30 45 16.0 Oct 03 R 15 47 13.7 Oct 03 R 15 49 13.9 Oct 03 R 15 73 14.0 Oct 03 R 30 55 15.2 Oct 03 R 30 53 15.0 Oct 03 R 15 35 15.0 Oct 03 R 15 29 15.3 Oct 03 R 30 53 15.6 Oct 03 R 30 59 14.2 Oct 03 C 20 100 14.4 Oct 03 R 15 64 15.4 Oct 03 R 20 47 15.3 Oct 03 R 30 38 15.7 Oct 03 C 20 45 15.6 Sep 03 R 30 98 14.6 Oct 03 R 30 50 15.5 Oct 03 R 30 50 15.4 Oct 03 R 30 55 15.2 Period (H) 5.75 ±0.001 6.47 ±0.01 7.05 ±0.01 4.277 ±0.001 6.354 ±0.001 12.97 ±0.01 3.678 ±0.001 6.19 ±0.01 10.98 ±0.01 11.95 ±0.01 15.25 ±0.01 13.7 ±0.1 4.876 ±0.01 6.325 ±0.001 7.310 ±0.005 Amp 0.52 0.30 0.18 0.15 0.20 0.23 0.18 0.25 0.36 0.50 0.33 0.28 0.23 0.37 0.45 * = Existing entry in Harris List as of Oct 2003 Figure 1. Signal to noise estimate for the Rigel telescope. APPENDIX: Composite lightcurves for 15 asteroids observed at the Winer Observatory, September – October 2003. Minor Planet Bulletin 31 (2004) 31 Minor Planet Bulletin 31 (2004) 32 Minor Planet Bulletin 31 (2004) 33 LIGHTCURVE PHOTOMETRY OF MARS-CROSSING ASTEROIDS 1474 BEIRA AND 3674 ERBISBUHL Robert A. Koff 980 Antelope Drive West Bennett, CO 80102 bob.koff@worldnet.att.net (Harris et al., 1989). This program allows compensation for nightto-night comparison star variation by manually shifting individual night’s magnitude scales to obtain a best fit. Observations and Results 1474 Beira (Received: 2 January) This is a report on the lightcurve measurement program at Antelope Hills Observatory in the United States. Asteroid 1474 Beira was determined to have a period of 4.184 hours ± 0.001 hours, with an amplitude of 0.18 ± 0.02 magnitude. Asteroid 3674 Erbisbuhl exhibited a period of 11.28 hours ±0.01 hours and an amplitude of 0.40 ± 0.02 magnitude. Equipment and Procedure In 2002, Antelope Hills Observatory was established as a replacement for Thornton Observatory, MPC code 713. The new observatory is located near Bennett, Colorado at an elevation of 1740 meters. The observatory has obtained the MPC code H09. The equipment and instrumentation of Antelope Hills Observatory consists of an 0.25-m f/10 Meade SCT telescope, a True Technology filter wheel, and an Apogee AP47 camera, operated unbinned. The instruments are housed in a clamshell dome, and are operated remotely from the nearby house. Targets were selected from the “Potential Lightcurve Targets” on the CALL website (Warner, 2003), and further refined based on their magnitude and position in the sky. Targets were selected for which no lightcurve data had been previously reported. (Harris, 1997). Mars-crossing asteroids were given priority. All images reported here were obtained in unfiltered light, using a clear filter with an IR cutoff of 700 nm to prevent fringing. The differential photometry was measured using the program “Canopus” by Brian Warner, which uses aperture photometry. Magnitudes were calculated using reference stars from the USNOA 2.0 catalog. Comparison stars differed from night-to-night due to movement of the asteroid. Lightcurves were prepared using “Canopus”, based on the method developed by Dr. Alan Harris Beira, a Mars-crossing asteroid, was discovered August 20, 1935 by C. Jackson at Johannesburg, S. A. It is approximately 19 km in diameter. The aphelion is 4.072 AU and the perihelion is 1.400 AU. No lightcurve results are reported for this object (Harris 2004). Observations were made on six nights during the period from September 2, 2003 to November 12, 2003. During the period of the investigation, the phase angle dropped from 35.5 degrees to 34.0 degrees before increasing to 40.75 degrees. Exposure times for this investigation were two minutes each. Images were taken at 2.5-minute intervals. Dark frames and flat fields were used to calibrate each image. A total of 463 observations were used in the solution. Figure 1 shows the resulting lightcurve. The zero point of the curve is J.D. 2452887.72249. The synodic period was determined to be 4.184 hours with a formal error of ± 0.001 hours. The amplitude was 0.18 ± 0.02 magnitude. Figure 1. Lightcurve of 1474 Beira, based on a period of 4.184 hours. Ordinate is relative magnitude. Minor Planet Bulletin 31 (2004) 34 3674 Erbisbuhl Erbisbuhl is a Mars-crossing asteroid discovered September 13, 1963 by C. Hoffmeister at Sonneberg. It is approximately 25 km in diameter. The aphelion is 3.243 AU, and perihelion is 1.479 AU. No previously observed lightcurve is reported for this object (Harris 2004). Observations were made on three nights during the period from December 17, 2003 to December 26, 2003. During the period of the investigation, the phase angle dropped from 15.5 degrees to 11.0 degrees. Exposure times for this investigation were two minutes each. Images were taken at 2.5-minute intervals. Dark frames and flat fields were used to calibrate each image. A total of 492 observations were used in the solution. Figure 2 shows the resulting lightcurve. The zero point of the curve is J.D. 2452990.75470. The synodic period was determined to be 11.28 hours with a formal error of ± 0.01 hours. The amplitude was 0.40 ± 0.02 magnitude. In addition to the clear filter images used in the period solution, four images were taken using V and R filters, and transformed to the standard system. The resultant V-R for asteroid 3647 was 0.47 with an estimated error of ±0.05. LIGHTCURVE ANALYSIS OF ASTEROIDS 110, 196, 776, 804, AND 1825 Donald P. Pray Carbuncle Hill Observatory P.O. Box 946 Coventry, RI 02816 dppray@hotmail.com (Received: 14 January Revised: 10 February) Lightcurve period and amplitude results are reported for five asteroids observed at Carbuncle Hill Observatory during November 2003 through January 2004. The following synodic periods and amplitudes were determined: 110 Lydia, 10.924+0.003h, 0.14+0.01m; 196 Philomela, 8.33+0.02h, 0 . 1 0+0.02m; 776 Berbericia, 7.67+0.04h, 0.26+0.01m; 804 Hispania, 14.64+0.01h, 0.20+0.02m; 1825 Klare, 4.744+0.009h, 0.75+0.02m Introduction Carbuncle Hill Observatory, MPC code 100, is located about twenty miles west of Providence, RI, in one of the darkest spots in the state. All observations were made using an SBIG ST-10XME CCD camera, binned 3x3, coupled to a 0.35m f6.5 SCT. This combination produced an image dimension of 21x14 arc min. All observations were taken through the “clear” filter. Figure 2. Lightcurve of 3674 Erbisbuhl, based on a period of 11.28 hours. Ordinate is relative magnitude. Acknowledgments Many thanks to Brian Warner for his continuing work on the CALL website and the program “Canopus”, which has made it possible for amateurs to analyze and share lightcurve data. References 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 Asteroids 3, 24, 60, 261, and 863.” Icarus 77, pp. 171-186. Harris, A. W. (2004). “Minor Planet Lightcurve Parameters”, On the Minor Planet Center website: http://cfa-www.harvard .edu/iau/lists/LightcurveDat.html, or on the CALL website: http://www.MinorPlanetObserver.com/astlc/default.htm Warner, B. D. (2003). “Potential Lightcurve Targets”, on the CALL website, http://www.MinorPlanetObserver.com/astlc/ default.htm Most of the selected asteroids were observed as part of the A.L.P.O. Shape Modeling Program. Details of this program may be found at http://www.bitnik.com/mp/alpo/. The aim of the program is to determine the pole position, shape, rotation state and surface scattering properties of asteroids. Lightcurves generated over several apparitions are generally required to make these determinations. The four asteroids selected for this study already had previously measured periods, so it is the differences between the newly-found lightcurves and those which preceded them that is significant. Targets were also selected based on their location above the local horizon, as well as for their suitability to the equipment. 1825 Klare was selected from the “Call” website’s “List of Potential Lightcurve Targets” (Warner 2003). This target did not have its period published in the list of “Minor Planet Lightcurve Parameters” maintained by Harris and Warner (2003). Image calibration via dark frames and flat field frames was performed using “MaxIm DL”. Lightcurve construction and analysis was accomplished using “Canopus” developed by Brian Warner. Differential photometry was used in all cases, and all measurements were corrected for light travel time. Observations and Results 110 Lydia Discovered by A. Borrelly at Marseille in 1870, 110 Lydia was determined to have a synodic period of 10.924+0.003h, with an amplitude of 0.14+0.01m. 597 images taken in ten sessions between December 2 and December 29, 2003 were used to make this measurement. The lightcurve is shown in Figure 1. This period is compared to 10.927h, with an amplitude ranging between 0.10 and 0.20m, which is presented in the list of Minor Planet Lightcurve Parameters, Harris and Warner (2003). The IRAS Minor Planet Bulletin 31 (2004) 35 Minor Planet Survey, as appears in the Small Bodies Node of NASA’s Planetary Data System, (henceforth IRAS V4.0), lists 110 Lydia as having an assumed absolute magnitude of 7.80, a mean albedo of 0.181, and an effective diameter of 86 km. maxima. If and when their shapes are determined, it should be interesting to see what form they take. The list of Minor Planet Lightcurve Parameters states this object as having a period of 7.668h with amplitude estimates between 0.13m and 0.21m. The mean albedo is stated as 0.066 with an assumed absolute magnitude of 7.68, yielding an effective diameter of 151 km, (IRAS V4.0). Figure 1. The lightcurve of 110 Lydia. The synodic period was found to be 10.924+0.003h with an amplitude of 0.14+0.01m. 196 Philomela C.H.F. Peters discovered this asteroid in 1879 at Clinton. IRAS V4.0 has estimated a diameter of 136 km for this object with an assumed absolute magnitude of 6.55. During three sessions between November 16 and November 23, 2003, 559 images were taken to derive a synodic period of 8.33+0.02h with an amplitude of 0.10+0.02m. See Figure 2. During this time, the phase angle changed from 8.6 to 6.3 degrees. The list of Minor Planet Lightcurve Parameters lists this object as having a period of 8.343h, with various amplitudes between 0.07 and 0.37m. Figure 3. The lightcurve for 776 Berbericia. The synodic period was determined to be 7.67+0.04h with an amplitude of 0.26+0.01m. 804 Hispania Hispania was discovered in 1915 at Barcelona by J. Comas Sola. The mean albedo is listed as 0.052 with an assumed absolute magnitude of 7.84, yielding an effective diameter of 157 km, (IRAS V4.0). Ambiguity seems to have followed this object throughout the years of effort to determine its rotational lightcurve period. The list of Minor Planet Lightcurve Parameters shows a period of 14.840h, and an amplitude between 0.19 and 0.23m. However, examination of the references provided in the list show other determinations have been made in the area of 7.4h, Magnusson and Langerkvist (1991), Calabresi and Roselli (2001). New lightcurve observations of Hispania were obtained from December 9 to December 28, 2003, during which a total of 177 images were taken during four sessions. My initial analysis showed a synodic period of 7.462+0.015h with an amplitude of Figure 2. The lightcurve of 196 Philomela. The synodic period was found to be 8.33+0.02h with an amplitude of 0.10+0.02m. 776 Berbericia This object was discovered at Heidelburg by A. Massinger in 1914. The synodic period was determined to be 7.67+0.04h with an amplitude of 0.26+0.01m. 386 images were taken in two sessions over a three-night span between November 24 and November 26, 2003. This asteroid is seen to have a somewhat unusual lightcurve with four maxima, although one of these is quite small. See Figure 3. Interestingly, it has roughly similar features to the lightcurve of 110 Lydia, which also shows four Figure 4. The lightcurve for 804 Hispania. The synodic period was found to be 14.64+0.01h with an amplitude of 0.24+0.01m. Minor Planet Bulletin 31 (2004) 36 0.20+0.02m. However, consultations with Robert Stevens of Santana Observatory led me to revise the period upward to nearly double this. Using his much larger data set as a guide for analysis, I now derive a period of 14.64+0.01h with an amplitude of 0.24+0.01m. However, there is a rather large hole in the curve, so these parameters could well change somewhat with better coverage. The lightcurve is shown in Figure 4. Acknowledgments Special thanks is given to Brian Warner for his continued help and support in my development in this area of research, and for his continuing improvements to the program, “Canopus”. Thanks are also given to Bob Stevens for his assistance with the solution of the 804 Hispania lightcurve. References 1825 Klare This asteroid was discovered by K. Reinmuth at Heidelberg in 1954. 438 images were taken between December 27, 2003 and January 1, 2004, in five sessions. The measured synodic period was 4.744+0.009h with an amplitude of 0.75+0.02m. The large amplitude would suggest a highly irregular shape. It was observed at phase angles varying from 6 to 3.5 degrees. The lightcurve is presented in Figure 5. Calabresi, M., and Roselli, G. (2001). “Research Note, The Rotation Period of 804 Hispania. Some Considerations on its Nature.” Astronomy and Astrophysics, 369, 305-307. Harris, Alan W., and Warner, Brian D. (2003). “Minor Planet Lightcurve Parameters”, found on the Minor Planet Center web site: http://cfa-www.harvard.edu/iau/lists/LightcurveDat.html. IRAS V4.0 from NASA Small Bodies Node of the Planetary Data System, IRAS Minor Planet Survey V4.0. http://pdssbn.astro .umd.edu/nodehtml/sbdb.html Magnusson, P., and Langerkvist, C. I. (1991). “Physical Studies of Asteroids XXII. Photoelectric Photometry of Asteroids 34, 98, 115, 174, 270, 389, 419 and 804.” Astronomy and Astrophysics Supplement Series 87, 269-275. Stevens, R. (2004). Private communications. .earthlink.net/~rdstephens/default.htm http://home Warner, B.D. (2003). Collaborative Asteroid Lightcurve Link (CALL) web site. http://www.MinorPlanetObserver.com/astlc/ default.htm. Figure 5. The lightcurve for 1825 Klare. The measured synodic period was 4.744+0.009h with an amplitude of 0.75+0.02m. LIGHTCURVE ANALYSIS FOR NUMBERED ASTEROIDS 1351, 1589, 2778, 5076, 5892, AND 6386 Brian D. Warner Palmer Divide Observatory 17995 Bakers Farm Rd. Colorado Springs, CO 80908 brian@MinorPlanetObserver.com (Received: 6 January Revised: 17 January) The lightcurves of six numbered asteroids obtained in late 2003 were analyzed. The following synodic periods and amplitudes were determined. 1351 Uzbekistania: 73.90±0.02h, 0.34±0.02m; 1589 Fanatica: 2.58±0.05h, 0.16±0.02m; 2778 Tangshan: 3.461±0.020h, 0.25±0.03m; 5076 Lebedev-Kumach: 3.2190±0.0005h, 0.14±0.02m; (5892) 1981 YS1: 10.60±0.02h, 0.26±0.03m; and (6386) 1989 NK1: 3.1381±0.0005h, 0.08±0.02m. Equipment and Procedures The asteroid lightcurve program at the Palmer Divide Observatory has been previously described in detail (Warner 2003) so only a summary is provided now. The main instrument at the Observatory is a 0.5m f/8.1 Ritchey-Chretien telescope using a Finger Lakes Instruments IMG camera with Kodak KAF-1001E chip. A second instrument also in use was a 0.3m f/9.3 SchmidtCassegrain using an SBIG ST-9E camera. For this set of asteroids, only the 0.5m scope was used. Initial targets are determined by referring to the list of lightcurves maintained by Dr. Alan Harris (Harris 2003), with additions made by the author to include findings posted in subsequent issues of the Minor Planet Bulletin. In addition, reference is made to the Collaborative Asteroid Lightcurve Link (CALL) web site maintained by the author (http://www.MinorPlanetObserver .com/astlc/default.htm) where researchers can post their findings pending publication. MPO Canopus, a custom software package written by the author, is used to measure the images. It uses aperture photometry with derived magnitudes determined by calibrating images against field or, preferably, standard stars. Raw instrumental magnitudes are used for period analysis, which is included in the program. The routine is a conversion of the original FORTRAN code developed by Alan Harris (Harris et al., 1989). Note: in the following, the orbital elements are taken from the IAU MPCORB data file available at the Minor Planet Center web site (ftp://cfa-ftp.harvard.edu/pub/MPCORB/). The date of osculation for the elements was 2453000.5. Minor Planet Bulletin 31 (2004) 37 The Phase Angle Bisector The observation table for each asteroid gives the date, phase angle, and phase angle bisector longitude and latitude. The PAB was developed by Alan Harris and Edward Bowell. Harris states (Harris 2003a), “The significance is that the direction that bisects the directions to the sun and the line of sight is a best approximation to a single ‘viewing direction.’ As an extreme example, if you viewed a rotating ‘cigar’ from its pole it would have no lightcurve amplitude if the sun were also shining from the pole direction, but if the sun were shining at the equator (90° phase angle), then you would see a big amplitude. Now if you reverse the Earth and sun positions so you are viewing from the equator and the sun is shining on the pole, you likewise get a big amplitude, even though in this case the illuminated area is constant, you just see different amounts of it as it rotates. The best approximation you can make to a zero phase angle viewing aspect is a single line half way in between the illumination and viewing directions. This we call the ‘phase angle bisector’, since it is the line that bisects the phase angle.” includes, among others, 48 Doris and 52 Europa. The IRAS survey (Tedesco 1989) gives an effective diameter of 64.91 ± 4.31km and mean albedo of 0.0606 ±0.0090. The IAUs MPCORB database gives values of 9.6 and 0.15 respectively for H and G. The principal orbital elements for Uzbekistania are: semimajor axis, 3.197AU; inclination, 9.703°; and eccentricity, 0.0610. There were 871 data points used in the final analysis that gave a synodic period of 73.90±0.02h and amplitude of 0.34±0.02m. Figure 1 shows the observations phased against this period. The amplitude implies a ratio of 1.37:1 for the projected a/b axes of the assumed triaxial ellipsoid. The table below provides a summary of the individual observation runs. 1589 Fanatica Results M. Itzigsohn discovered 1589 Fanatica on 1950 September 13 at La Plata. The name is in honor of Eva Peron whose devotion and enthusiasm for the people of Argentina led her to champion the cause of workers. The name literally means a fanatical woman or feminine zealot. The asteroid has been designated 1935 RD, 1937 CF, 1946 OE, 1950 RK, 1950 TM3, and A924 WC. Uzbekistania was discovered by G.N. Neujmin at Simeis on 1934 October 5. It’s carried the designations 1925 CA, 1928 QJ, 1931 FK, 1934 TF, A917 SL, and A920 FA. It’s named in honor of the (former) Uzbek Soviet Republic where the discoverer lived during WW II. Kozai (1979) puts the asteroid in his group 63, which The H value from the MPCORB database 12.00. Using a formula provide by Harris (2003), which assumes the asteroid’s albedo (0.18) and type (S) based on the semi-major axis, the approximate diameter is 12 km. Kosai (1979) includes Fanatica in his group 15 along with 11 Parthenope and 17 Thetis. The principal elements are: semi-major axis, 2.417AU; inclination, 5.261°; and eccentricity, 0.0927. 1351 Uzbekistania Observations were obtained on three nights in late November and early December, with a total of 261 data points used in the final period analysis (see Figure 2). The synodic period was found to be 2.58±0.05h and the amplitude to be 0.16±0.02m, or a projected Figure 1. The lightcurve for 1351 Uzbekistania. The synodic period is 73.9±0.02h and the amplitude 0.34±0.02m. DATE 2003 Oct. Oct. Nov. Nov. Nov. Nov. Nov. Nov. Nov. 09 12 04 15 16 17 19 21 24 Phase Angle 15.0 14.3 7.7 4.5 4.3 4.1 3.8 3.6 3.7 PAB Long 58.2 58.5 59.4 59.4 59.4 59.4 59.4 59.4 59.4 Lat 7.5 7.6 8.6 9.0 9.0 9.1 9.1 9.2 9.3 Figure 2. The lightcurve for 1589 Fanatica phased against a synodic period of 2.58±0.05h. The amplitude is 0.16±0.02m. DATE 2003 Nov. 29 Nov. 30 Dec. 01 Minor Planet Bulletin 31 (2004) Phase Angle 7.9 8.4 8.9 PAB Long 52.7 52.8 52.8 Lat –4.1 –4.0 -4.0 38 a/b ratio of 1.16:1 for the assumed triaxial ellipsoid. The table below provides a summary of the individual observation runs. 2778 Tangshan amplitude to be 0.14±0.02m. Assuming a triaxial ellipsoid, the amplitude gives a ratio of 1.14:1 for the projected a/b axes. Figure 4 shows a phased plot against this period. The table below provides a summary of the individual observation runs. Tangshan is named for a city in the Hebei province in northern China. It was discovered at the Purple Mountain Observatory at Nanking on 1979 December 14. Its last designation was 1979 XP with its earliest designation being 1948 WL. Using the formula by Harris (2003), the approximate diameter is 8 km when using the MPCORB H value of 13.00 and albedo of 0.18. The principal elements are: semi-major axis, 2.281AU; inclination, 4.616°; and eccentricity 0.1212. Figure 3 shows the 265 data points obtained on Nov. 26 and Nov. 28, 2003, that were used in the final period analysis. The synodic period of the lightcurve is 3.461±0.020h and its amplitude is 0.25±0.03m, which yields a projected a/b axis ratio of 1.26:1 for the assumed triaxial ellipsoid. The table below provides a summary of the individual observation runs. Figure 4. The lightcurve for 5076 Lebedev-Kumach. The synodic period is 3.2190±0.0005h with an amplitude of 0.14±0.02m. DATE 2003 Oct. 05 Nov. 15 Nov. 25 Phase Angle 6.2 25.8 28.3 PAB Long 2.3 8.8 11.6 Lat 1.1 –2.7 –3.5 Figure 3. The lightcurve for 2778 Tangshan. The data is phased against a synodic period of 3.461±0.020h. The amplitude is 0.25±0.03m. DATE 2003 Nov. 26 Nov. 28 Phase Angle 2.5 3.3 PAB Long 61.1 61.2 Lat –3.4 –3.3 5076 Lebedev-Kumach Discovered by L. I. Chernykh on 1973 September 26 at Nauchnyj, Lebedev-Kumach is named for Vasilij Ivanovich LebedevKumach (1898-1949), prominent poet and song-writer, known for his lyrical and patriotic verses for songs for many Soviet films. The principal elements are: semi-major axis, 2.416AU; inclination, 9.481°; and eccentricity 0.2327. Assuming an albedo of 0.18 per Harris (2003) and the H value of 13.00 from the MPCORB data file, the approximate diameter is 8 km. Observations were obtained in October and November 2003, with 150 data points used in the final period analysis. The synodic period of the lightcurve was found to be 3.2190±0.0005h and the Figure 5. A phased lightcurve for (5892) 1981 YS1 using a synodic period of 10.60±0.02h. The amplitude is 0.26±0.03m. DATE 2003 Dec. Dec. Dec. Dec. Minor Planet Bulletin 31 (2004) 10 11 13 14 Phase Angle 12.5 13.1 14.2 14.7 PAB Long 64.0 64.2 64.6 64.8 Lat –7.6 –7.6 -7.6 -7.5 39 Acknowledgments (5892) 1981 YS1 This is another discovery from Purple Mountain Observatory at Nanking (1981 December 23). The asteroid has also carried the designations 1971 BS1, 1988 QG1, and 1988 UZ. Again using the formula from Harris (2003) and assumed albedo of 0.18, the H value of 13.60 gives an approximate diameter of 6 km. The principal elements are: semi-major axis, 2.384AU; inclination, 4.585°; and eccentricity 0.3020. 358 observations obtained on four nights in December 2003 were used to find a synodic period for the lightcurve of 10.60±0.02h and amplitude of 0.26±0.03m. The latter implies a ratio of 1.27:1 for the projected a/b axes of a triaxial ellipsoid. Figure 5 shows a phased plot of the observations and the table below gives a summary for each run. (6386) 1989 NK1 H.E. Holt discovered 1989 NK1 on 1989 July 10 at Palomar. It has also been designated 1955 RG1 and 1991 FW4. Assuming an albedo of 0.18, based on Harris (2003), and using the H value of 12.70 from the MPCORB table, the approximate diameter is 9 km. The principal elements are: semi-major axis, 2.271AU; inclination, 8.737°; and eccentricity 0.3008. Observations were made in October and November 2003. The 211 data points used for analysis are shown in Figure 6 against the derived synodic period of 3.1381±0.0005h. The amplitude of the curve is 0.08±0.02m. This would give a ratio of 1.08:1 for the projected a/b axes of a triaxial ellipsoid. The table below provides the viewing aspects for each of the observation runs. Thanks go to Dr. Alan Harris of the Space Science Institute for making available the source code to his Fourier Analysis program and his continuing support and advice. I also thank Robert D. Stephens of Santana Observatory, Rancho Cucamonga, for his ongoing advice and support. References References Note: Asteroid names and discovery information are from Schmadel (1999). 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 Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186. Harris, Alan W. (2003). “Minor Planet Lightcurve Parameters. On Minor Planet Center web site: http://cfawww.harvard.edu/iau/lists/LightcurveDat.html Harris, Alan W. (2003a). Private communications. Kozai, Y., (1979). “The dynamical evolution of the Hirayama family.” In Asteroids (T. Geherels, Ed.) pp. 334-358. Univ. of Arizona Press, Tucson. Schmadel, L. (1999). Dictionary of Minor Planet Names, 4th edition. Springer-Verlag, Heidelberg, Germany. Tedesco, E. F., Tholen, D.J., and Zellner, B. (1989). “UBV colors and IRAS alebedos and diameters”. In Asteroids II (R.P. Binzel, T. Gehrels, and M.S. Matthews, Eds.), pp. 1090-1138. Univ. of Arizona Press, Tucson. Warner, B. D. (2003), “Lightcurve Analysis for [Several] Asteroids”, Minor Planet Bulletin 30, 21-24. CALL FOR OBSERVATIONS Frederick Pilcher Illinois College Jacksonville, IL 62650 USA Figure 6. A phased lightcurve for (6386) 1989 NK1 using a synodic period of 3.1381±0.0005h. The amplitude is 0.08±0.02m. DATE 2003 Oct. Nov. Nov. Nov. 15 04 10 14 Phase Angle 14.9 15.9 17.9 19.3 PAB Long 27.1 31.4 32.8 33.8 Lat -15.7 -15.4 -15.1 -14.8 Observers who have made visual or photographic measurements of positions of minor planets in calendar 2003 are encouraged to report them to this author on or before April 1, 2004. This will be the deadline for receipt of reports which can be included in the “General Report of Position Observations for 2003,” to be published in MPB Vol. 31, No. 3. Minor Planet Bulletin 31 (2004) 40 PHOTOMETRY OF 804 HISPANIA, 899 JOKASTE, 1306 SCYTHIA, AND 2074 SHOEMAKER Date Robert D. Stephens 11355 Mount Johnson Court Rancho Cucamonga, CA 91737 USA rstephens@foxandstephens.com 2003/10/07 2003/10/08 2003/10/09 2003/10/12 2003/10/13 (Received: 19 December) Phase Angle 4.9 4.8 4.8 4.9 5.1 PAB (Long.) 16.4 16.4 16.4 16.4 16.4 PAB (Lat.) 9.6 9.7 9.8 10.0 10.1 No. Obs. 130 151 151 173 165 Table I: Observing circumstances for 804 Hispania 899 Jokaste Results for the following asteroids (lightcurve period and amplitude) observed from Santana Observatory during the period September to December 2003 are reported: 804 Hispania (14.845 ± 0.01 hours and 0.21 mag.), 899 Jokaste (6.245 ± 0.005 hours and 0.28 mag.), 1306 Scythia (15.05 ± 0.01 hours and 0.18 mag.), 2074 Shoemaker (57.02 ± 0.1 hours and 0.45 mag.). 899 Jokaste is a main-belt asteroid discovered August 3, 1918 by M. Wolf at Heidelberg. It is probably named for a figure in the opera Die Fledermaus by Johann Strauss. Three hundred one observations over three sessions between November 27 and December 3, 2003 were used to derive the synodic rotational period of 6.245 ± 0.005 hours with an amplitude of 0.28 ± 0.02 magnitude. Table II gives the observed range of phase angles. Santana Observatory (MPC Code 646) is located in Rancho Cucamonga, California at an elevation of 400 meters and is operated by Robert D. Stephens. Details of the equipment and reduction techniques are found in Stephens (2003) and at the author’s web site (http://home.earthlink.net/~rdstephens/ default.htm). All of the asteroids were selected from the “CALL” web site “List of Potential Lightcurve Targets” (Warner 2003). Shoemaker was selected because it is a Hungaria asteroid and because it is named in honor of Eugene Shoemaker. 804 Hispania Discovered March 20, 1915 by J. Comas Solá at Barcelona, Hispania is a main-belt asteroid. Hispania is the Latin name of Spain. Seven hundred sixty nine observations over five sessions between October 7 and 13, 2003 were used to derive the synodic rotational period of 14.845 ± 0.01 hours with an amplitude of 0.21 ± 0.02 magnitude. Table I gives the phase angles during the observing run. Figure 2: Lightcurve of 899 Jokaste based upon a derived period of 6.245 ± 0.005 hours. Zero phase equals J.D. 2452975.801180 (corrected for light-time). Date 2003/11/27 2003/12/02 2003/12/03 Phase Angle 1.8 1.2 1.6 PAB (Long.) 67.3 67.4 67.4 PAB (Lat.) 1.9 1.5 1.4 No. Obs. 104 73 124 Table II: Observing circumstances for 899 Jokaste 1306 Scythia Figure 1: Lightcurve of 804 Hispania based upon a derived period of 14.845 ± 0.01 hours. Zero phase is J.D. 2452920.867512 (corrected for light-time). Discovered July 22, 1930 by G. N. Neuymin at Simeïs, Scthia is a main-belt asteroid. It is named for the country of the ancient Scythians, comprising parts of Europe and Asia in regions north of the Black sea and east of the Aral Sea. Its estimated size is 34 km in diameter. Three hundred eighty four observations over four sessions between September 23 and 30, 2003 were used to derive the synodic rotational period of 15.05 ± 0.01 hours with an amplitude of 0.18 ± 0.03 magnitude. Table III gives the phase angles during the observing run. Minor Planet Bulletin 31 (2004) 41 Figure 3: Lightcurve of 1306 Scythia based upon a derived period of 15.05 ± 0.01 hours. Zero phase equals J.D. 2452908.860012 (corrected for light-time). Date 2003/09/23 2003/09/26 2003/09/29 2003/09/30 Phase Angle 9.1 8.5 8.1 8.0 PAB (Long.) 12.5 12.5 12.6 12.6 PAB (Lat.) 18.5 18.6 18.6 18.6 No. Obs. 72 101 109 102 Table III: Observing circumstances for 1306 Scythia 2074 Shoemaker 2074 Shoemaker is a Hungaria asteroid discovered by E. Helin at Palomar on October 17, 1974. It is named in honor of Eugene Shoemaker (1928-1997). Based upon its H value, Shoemaker is estimated to be between 4 and 9 km in size. Seven hundred twenty two observations over nine nights between October 15 and November 3, 2003 were used to derive the synodic rotational period of 57.02 ± 0.10 hours with an amplitude of 0.45 ± 0.03 magnitude. Its long period made it very difficult to get adequate overlap between the sessions. Each session contributed barely 10 percent to the lightcurve. Finally, the California wildfires, which burned to within a half a kilometer of the observatory curtailed observations until the asteroid was too low to observe. Because the asteroid was moving so fast, each night had to be split into two sessions with different comparison stars which were corrected with zero point adjustments. Table IV gives the phase angles during the observing run. Figure 4: Lightcurve of 2074 Shoemaker based upon a derived period of 57.02 ± 0.10 hours. Zero phase equals J.D. 2452929.762632 (corrected for light-time). Date 2003/10/15 2003/10/16 2003/10/17 2003/10/18 2003/10/19 2003/10/20 2003/10/21 2003/10/23 2003/11/03 Phase Angle 4.9 4.5 4.2 4.2 4.3 4.7 5.1 6.4 15.0 PAB (Long.) 22.1 22.1 22.0 22.0 22.0 22.0 22.0 21.9 22.1 PAB (Lat.) 5.7 5.3 4.9 4.4 4.0 3.6 3.2 2.4 -2.1 No. Obs. 86 82 103 81 76 78 87 95 34 Table IV: Observing circumstances for 2074 Shoemaker Acknowledgements Many thanks to Brian Warner for his continuing work and enhancements to the software program “Canopus” which makes it possible for amateur astronomers to analyze and collaborate on asteroid rotational period projects and for maintaining the CALL Web site which helps coordinate collaborative projects between amateur astronomers. References Stephens, R. D. (2003). “Photometry of 2134 Dennispalm, 2258 Viipuri, 3678 Mongmanwai, 4024 Ronan, and 6354 Vangelis.” MPB 30, 46-48. Stephens, R. D. (2003). http://home.earthlink.net/~rdstephens/default.htm. Warner, B. (2003). “Potential Lightcurve http://www.minorplanetobserver.com/astlc.targets. Minor Planet Bulletin 31 (2004) Targets.” 42 CCD PHOTOMETRY OF 1248 JUGURTHA Walter E. Worman Department of Physics and Astronomy Minnesota State University Moorhead Moorhead, MN 56563 Michael P. Olson Department of Physics North Dakota State University Fargo, ND 58105 (Received: 8 December Revised: 11 January) CCD observations were made of 1248 Jugurtha on four nights in February and March 2002. The synodic period of rotation was found to be 12.190 ± 0.002 hours with the lightcurve amplitude evolving from 0.827 ± 0.017 to 0.734 ± 0.017 magnitudes. The period and large amplitude are in agreement with previously reported values. the sum of the squares of the residuals. The resulting values were a period of 12.190 ± 0.002 hours, the additive constant for the second night was –0.0875, for the third night was –0.4719, and for the fourth night was 0.3297 magnitudes. These are reasonable as the uncertainties in the Hubble Guide Star Catalog are given to be about ± 0.4 magnitudes. The standard deviation of the residuals was 0.017 magnitudes, which is due to the amplitude difference of the last night compared to the previous three. A period of 12.190 hours was assumed and the second through fourth night data were translated to fall on the first night data to give the composite lightcurve shown in Figure 1. The time scale is given in rotational phase with the zero corresponding to 0 hr on February 17, 2002 UT. There are clearly two maxima and two minima per rotation. The amplitude of the lightcurve is 0.827 ± 0.017 magnitudes for the first day and 0.734 ± 0.017 magnitudes for the last day. The phase angle during the first three days of observations varied between 8.9° and 7.3°, and the last day was 5.4°. We believe that this phase angle change is responsible for the amplitude trend as less shadowing occurs on the asteroid at smaller phase angles. Reference Observations The asteroid 1248 Jugurtha is a main-belt asteroid with semimajor axis of 2.72 AU. Koff and Gross (2002) previously reported a period of 12.1897 ±0.0001 hours with an amplitude in excess of 0.70 magnitudes. The new observations of 1248 Jugurtha we report here were made at the Paul Feder Observatory, located on the Buffalo River Site of the Minnesota State University Moorhead Regional Science Center. Data were collected on the nights of February 17, 21, 22, and March 10, 2002. The observatory has a 16-inch computer controlled Cassegrain telescope made by DFM. The associated Photometrics Star 1 CCD camera system was used to collect data. In all, 147 images were made of the asteroid during the four nights. Of these, 141 were used in the analysis. The others were rejected because the asteroid image was too close to another star or to dawn. The exposures were 3 minutes long and typically separated by 10 minutes. No filter was used. Dark current and flat field corrections were made to the data. Three stars were used as magnitude standards for each image. The magnitudes were taken from the Guide 7 program (Hubble Guide Star Catalog). A least squares fit was done for each image and the relation between the magnitude and the log of the total count determined. The magnitude of the asteroid was then determined from this relationship. A photometric aperture of 11 pixels by 11 pixels was used and an equal sized region of the background nearby was used for the background correction. Koff, R.A. and Gross, J. (2002). “Lightcurve Photometry of Asteroid 1248 Jugurtha.” MPB 29, 75-76 Figure 1. Rotational lightcurve for 1248 Jugurtha assuming a period of 12.190 hours. The V magnitude scale is approximate owing to the typical 0.4 mag. uncertainty of the Hubble Guide Star Catalog. Results Times were corrected for travel time from the asteroid to the Earth and were taken to be at the mid-times for the images. Lightcurves were made for each of the four nights. Relative magnitudes from night to night were uncertain as different comparison stars were used. This was dealt with by using additive constants for the second, third and fourth night magnitudes to bring them into agreement with the first night. A single lightcurve for the four nights was then least squares fit to a Fourier series including nine harmonics. The additive constants for the second through fourth nights and the period were then adjusted so that the fit minimized Minor Planet Bulletin 31 (2004) 43 THE MINOR PLANET OBSERVER: MAKING AND READING HISTORY Brian Warner Palmer Divide Observatory 17995 Bakers Farm Rd. Colorado Springs, CO 80908 brian@MinorPlanetObserver.com The news came in mid-October, 2003: the long lost minor planet 1937 UB, also known as Hermes, had been recovered. Brian Skiff of the Lowell Observatory Near-Earth-Object Search (LONEOS) program made the observations that sent astronomers, professional and amateur, scurrying to their instruments. Within a few days, radar and optical observations confirmed that the asteroid was actually two separate bodies rotating around one another. You can read more about the recovery at http://www.lowell.edu/press_ room/releases/recent_releases/Hermes_rls.html. As often happens with the announcement of an NEO discovery or recovery, there was a rush to gather as much data as possible. In some cases, that amounted to “overkill” as the Minor Planet Center received 50 or more astrometric observations a night in the days immediately following recovery. That’s not meant to discourage or disparage those who did turn in the observations. Only to note that one wishes there could be such interest more often, even when the targets are more mundane. I was one of those who jumped into the rush to get optical lightcurve data to support findings being reported by radar imaging teams. Two teams of optical observers took the fore on acquiring the data and analyzing it. One was lead by Petr Pravec at Ondrejov Observatory, of which I was a part, and Raoul Behrend of Geneva Observatory headed the other. A total of about 15 observers from Europe, Australia, and the U.S. contributed data that eventually lead to the finding of an orbital period for the pair of about 13.9h with an amplitude of 0.07m. The analysis further indicated that the objects appear to be locked in synchronous rotation. It never ceases to amaze me that one can make such determinations for asteroids based simply on the changing brightness over time. The feat becomes even more amazing when applied to eclipsing binary stars, which I’ve done with the aid of the program, Binary Maker by David Bradstreet. What the episode demonstrates is the value of cooperation and collaboration among professionals and among professionals and amateurs. Hermes was a difficult target, not so much because of its brightness or motion across the sky but because of the low amplitude of the curve and the uncertainty of the initial results. This was one time where overwhelming the problem with data was not a waste of time and effort but a strong necessity. Most readers of these pages don’t need to be told that pro-am collaborations can lead to a number of important discoveries and continued advancement in many aspects of astronomy. There are already many such collaborations among those involved in asteroids and eclipsing binary stars. Those collaborations have helped lead to some important developments in recent years and will continue to do so. There are many amateurs available who can and do high-level work every day (or night). The problem is getting them tied up with professionals who can do the critical analysis if they have the data. annual meeting in Big Bear, CA, each year. The group changed its name in 2003 and is working towards developing a method and process – a network, if you will – to build a pool of high quality observers and give professionals access to that pool. This parallels the work that has long be done by the American Association of Variable Star Observers (AAVSO) with whom SAS is trying to work along with other groups. If you’d like more information on SAS, visit their home page at http://www.socastrosci.org. One of the pleasures I had while out working on Hermes and other asteroids late in 2003 was to see a spectacular aurora. It’s rare to see much, if anything, from my mid-latitude location in Colorado but the heightened solar activity resulted in some spectacular shows of bright green curtains, blood red sheets, rays of all lengths and colors seen by those as far south as the southern tier of the United States. Of course, one man’s treasure is another man’s junk. Some Canadian amateurs were quick to point out that while the show was nice, they see such displays quite often with many so bright that the sky becomes is as if the quarter moon or more was present. This brought to mind a time when I was doing some visual variable star estimates and couldn’t figure out why the faint variable suddenly disappeared. I looked up to see almost the entire sky filled with sheet upon sheet of bright red aurora. I may marvel at such a display now, but I’ll also wonder if a few hundred miles north some other amateur is cursing Mother Nature. I’ve been reading a very well done book called “Galileo’s Daughter” by Dava Sobel (ISBN 0-8027-1343-2). It’s not new, having been published in 1999, but if you haven’t had a chance to read it, I recommend it very highly. It’s a tremendous and touching insight into Galileo’s writings and times using in part some or all of the 124 letters written by one of two of his daughters, both of whom he placed in a convent before their sixteenth birthday. It’s an unfortunate part of history that his letters to her did not survive. The mother abbess of the convent destroyed them soon after Suor Maria Celeste’s death in fear of reprisals from the Church for having the materials of a declared heretic. I also managed to read – finally – Donald Yeoman’s book on comets. This time I was about two decades behind the times. I think what started the reading frenzy was getting bogged down in the technical side of observing. It’s been a nice diversion to learn a little more about the history and people in astronomy. It also meant renewing a library card that was so old and infrequently used that the library district didn’t think I was still alive. I was glad to report such was the case and have rediscovered the joy of just wandering through the library during my lunch hour from time to time. There’s something old and something new around every corner just waiting to be discovered. With northern summer rapidly approaching, and so the asteroids dipping well south of the celestial equator, I’ll be taking more time to read some history, and traveling to one or more meetings. I particularly look forward to the latter as it gives me a chance to meet with some of you and learn how to improve my observing and data analysis skills. I hope to see some new faces and help develop new cooperative efforts among professionals and amateurs. Let there be no doubt: the day of the amateur is far from over despite the new large scopes and surveys coming on line. Clear Skies! Addressing this problem is just one goal of the Society for Astronomical Sciences, formerly the IAPPP-West, which holds an Minor Planet Bulletin 31 (2004) 44 LIGHTCURVES AND ROTATIONAL PERIODS OF 1474 BEIRA, 1309 HYPERBOREA, AND 2525 O'STEEN Gordana Apostolovska Institute of Physics, Faculty of Natural Sciences 1000 Skopje Republic of Macedonia gordanaa@iunona.pmf.ukim.edu.mk Violeta Ivanova, Galin Borisov Institute of Astronomy, Bulgarian Academy of Sciences BG-1786 Sofia Bulgaria ivanova@astro.bas.bg, gborisov@astro.bas.bg (Received: 15 January On 21 September 2003, three days before Beira's particularly favorable opposition, the asteroid was observed in B, V, R and I bands. All frames were taken through a standard Johnson-Cousins set of filters. The reduction to the BVRI standard system of the asteroid magnitudes was made by means of the observations of two standards fields SA114 and PG0231+051 (Landolt, 1992). The atmospheric extinctions were kB=0.32±0.03, kV=0.15±0.02, kR=0.140±0.036 and kI=0.07±0.01. The mean values of the color indices of the asteroid were measured as: B-V=0.70±0.049, V-I=0.687±0.012, R-I=0.314±0.006, and V-R=0.378±0.025. Revised: 5 February) The V-band lightcurves of the asteroids 1474 Beira, 1309 Hyperborea, 2525 O'Steen, and the mean color indices for 1474 Beira are presented. The CCD observations were carried out at the Bulgarian National Astronomical Observatory Rozhen (MPC Code 071). The calculated synodic periods are: 1474 Beira, 4.184±0.002h; 1309 Hyperborea, 13.95±0.02h; and 2525 O'Steen, 3.55±0.01h. The observations we report for 1309 Hyperborea, 1474 Beira, and 2525 O'Steen were made at the Bulgarian National Astronomical Observatory Rozhen (MPC Code 071). The data for Beira and O'Steen were obtained with an SBIG ST-8E (Kodak KAF-1602E, 1536x1024px2, 1px=9µ m) CCD camera attached to a 0.50m/0.70m Schmidt telescope. A Photometrics CCD camera (CE200A-SITe, 1024x1024, 1px=24µm) was used with the 2-m RCC for observing of Hyperborea. Until our choice of these objects, there was no reported information for photometric observations of these asteroids in the list of Harris (2003). In the preliminary reduction, images were dark and flat field subtracted. The flat field correction with precision <1% was made using twilight and dawn sky flat fields. The V-band lightcurves were derived from the differential magnitudes between the asteroid and comparison stars. Aperture photometry was performed using the software program CCDPHOT (Buie, 1998). For lightcurve analysis, we used Asteroid Catalog Software (APC) (Magnuson et al. 1990), that produces composite lightcurves, calculates rotational periods, and provides the Fourier analysis fitting procedure of the lightcurve, which we used. 1474 Beira Beira is a Mars-crossing asteroid with a semi-major axis of 2.74 AU, eccentricity 0.49 and inclination of orbit 26.7 degrees. Beira was discovered in 1935 by C. Jackson in Johannesburg. The assumed diameter of Beira in the IRAS Minor Planet Survey, (Tedesco, 1992) is 39 km. The Tholen taxonomic type (Tholen, 1989) is FX. At the time of observation asteroid was at 14.6m and the solar phase angle was 31.5 degrees. On 24 and 25 of August 2003, Beira was observed for about 6 hours, an interval that was more than the full lightcurve coverage. We determined the synodic period to be 4.184±0.002 hours. The amplitude of the composite lightcurve, Fourier fitted of order 6, is 0.149±0.010 magnitude. The obtained composite lightcurve has maxima and minima which slightly differ from each other by shape and height. Figure 1: Lightcurve of 1474 Beira based on a period of 4.184±0.002 hours. Figure 2: Lightcurve of 1309 Hyperborea based on a period of 13.95±0.014 hours. (1309) Hyperborea Hyperborea is a main-belt asteroid discovered in 1931 by G. N. Neujmin in Simeis. It has a semi-major axis of 3.20 AU, eccentricity 0.15 and inclination of orbit 10.28 degrees. The diameter of Hyperborea is 59 km (Tedesco, 1992). The observations of this asteroid at Rozhen were carried out in two nights: 12 and 14 January 2002. On the first night, bad weather conditions permitted only 2 hours of observations. The second night of observations cover 7.5 hours of the lightcurve, which reveals a nice maximum and very sharp minimum. Assuming a standard lightcurve with two pairs of symmetrical extrema we estimate a period of 13.95±0.02 hours. The amplitude of the Minor Planet Bulletin 31 (2004) 45 composite lightcurve for the presented phase interval is about 0.4 magnitude. Tholen, D. J., (1989). “ Asteroid taxonomic classifications.” In Asteroids II (R. P. Binzel, T. Gehrels, and M. S. Matthews, Eds.), pp 1139-1150. Univ. Arizona Press, Tucson. (2525) O'Steen This asteroid was discovered in 1981 by B. A. Skiff in Flagstaff at the Anderson Mesa Station. O'Steen is a main-belt asteroid with a semi-major axis of 3.13 AU, eccentricity 0.195 and inclination of orbit 2.78 degrees. The assumed diameter of 2525 O’Steen is 106 km (Tedesco, 1992). O'Steen was observed on 23 of September 2003. In the time of the observation the asteroid was 14m and the solar phase angle was 6.98 degrees. One night observations with a duration of 6 hours covered more than one cycle of the asteroid. The composite lightcurve based on a synodic period of 3.55±0.01 hours is asymmetric. The amplitude of the composite lightcurve, Fourier fitted of order 4, is 0.193±0.009 magnitude. BOOK REVIEW Richard P. Binzel, Editor A Practical Guide to Lightcurve Photometry and Analysis by Brian D. Warner. Bdw Publishing, 2003. ISBN 0-9743849-0-9, paperback, 266 pages. (Price $30, available at www.MinorPlanetObserver.com) Oh how long we have waited for a book like this! In the distant past, amateurs had to crack their way into the field of lightcurve photometry by tackling papers such as Hardie (1959) and by building their own photometers following the classic book by Frank Bradshaw Wood (1963). Several follow-on books that carried the field forward were published by Willmann-Bell, Inc., including Genet (1983) and Henden and Kaitchuck (1990). The affordability, proliferation, and enabling capabilities of CCD cameras at “amateur” observatories has opened a huge potential for new opportunities for new observers to make valuable lightcurve photometry measurements. Yet a void has existed in detailing how to get started and carry forward a program of lightcurve photometry driven by scientific curiousity. Figure 3: Lightcurve of 2525 O'Steen based on a period of 3.55± 0.01 hours. The Fourier fit of order 4 is presented with solid line. Acknowledgments This research was supported by contract Num, NZ-904/99 with the National Science Fund, Ministry of Education and Sciences, Bulgaria and by contract with the Ministry of Education and Science, Republic of Macedonia. References Buie, M. W., (1998). http://www.lowell.edu/users/buie/idl /ccdphot.html Harris, A. W. (2003). “Minor Planet Lightcurve Parameters”. On the Minor Planet Center website: http://cfa-www.harvard.edu /iau/lists/LightcurveDat.html (updated October 2003) Landolt, A.U., (1992). “UBVRI Photometric standard stars in the magnitude range 11.5<V<16.0 around the celestial equator”. Astron. J. 104, 340-491 Magnuson , P. and Lagerkvist, C. I., (1990). “Analyses of asteroid lightcurves. I. database and basic reduction.” Astron. Astrophys. Suppl. Ser. 86, 45-51 Tedesco, E., F. (Ed.), 1992. IRAS Minor Planet Survey, (Phillips Laboratory Technical Report No. PL-TR-92-2049. Hanscom Air Force Base, MA) Brian D. Warner’s Practical Guide now fills that void. It is written from the perspective of one who still remembers what it was like to start as a beginner. Thus the writing comes across in a warm and welcoming style. Much advice comes from Warner’s own experience, building upon works like Henden and Kaitchuck (1990), and it is conveyed as being told from one friend to another. It is hard to imagine any new person who picks up this book with genuine interest being able to resist taking the author’s extended hand and gently being guided forward. Warner first coaxes his readers to take the plunge by tantalizing them with the science that comes out of the observations. Those who try CCD lightcurve photometry because of the technical challenge will do it once or twice and then move to the next challenge elsewhere. This book’s approach is to capture you for the long term by getting you hooked on the joy and satisfaction of learning and contributing new scientific knowledge about our Universe. It is this common passion for new knowledge that erases barriers between “amateur” and professional astronomers. There are no barriers here. About 40 pages of the book are devoted to communicating the fundamentals of photometry, and this is accomplished with the clear and concise skill of a patient and expert teacher. Many references here (and in the book’s Bibliography) tell you where to go for more depth than this overview allows. Technical terms are given in italics when first introduced and a nice (although limited in length) Glossary is given at the end for additional help. Throughout the book, text blocks are offset within boxes displaying the subheading “Tying It Together…” to try to keep the big picture in mind while focusing on the details. Because computers and software are so intertwined with CCD data collection and reduction, the bulk of this book provides a guide to how to use these tools. While Warner himself has developed a wide variety of excellent and popular software tools, he does not exclusively tout his own packages. Most importantly, the author Minor Planet Bulletin 31 (2004) 46 tries to convey an understanding of what the various reduction steps are intended to accomplish. Numerous correct and fully warranted cautionary statements are made not to place blind trust in the output of these packages, but to give careful human thought as to whether the results being spit out make sense. The copious examples serve to help a beginner to learn rapidly many of the most common pitfalls. Ultimately it is the experience that the new observer gains with her/his own data that brings about confidence and expertise. Brian D. Warner’s Practical Guide is an instant classic and required reading for anyone learning the ropes of CCD photometry and its application to the challenge of lightcurve observations of both asteroids and variable stars. More than any other volume in the past decade, this book will spark new interest and new observers to the field of lightcurve studies. Thank you Brian for illuminating the way. We welcome all who follow. New observers who are ready to start their own programs will find advice on how to get off the ground and choose targets to begin working on. Recognizing that the higher purpose is to communicate one’s results, one of the final sections of the book describes the task and venues for publication, including the Minor Planet Bulletin. Many details and technical examples are saved for the Appendices, making the main body of the text smoothly flowing and readable. Finally the inclusion of standard star fields, reprinted with permission, puts some enormously useful reference material into a single accessible place. The quality and clarity of the printing of the standard star charts enables excellent photocopies of these pages – for personal use and handling ease at the telescope or computer screen. Genet, R. M. (1983). Solar System Photometry Handbook. Willmann-Bell, Inc., Richmond, VA. LIGHTCURVE PHOTOMETRY OPPORTUNITIES APRIL – JUNE 2004 For many years, the thrust of this article has been to get lightcurves on any object since the number of well-established lightcurve parameters was woefully small. The list of spin axis values was nearly non-existent. In recent years, there has been a dramatic increase in the number of entries on both lists, which are just now beginning to tell part of the tale of the true evolution of the asteroid system. This is no time to rest on our laurels but, with the promise of even more exciting and important discoveries to be made for the want of more observations, to reinforce our determination. Again, let there be no doubt that observations will be put to use. The fear that they will be lost in the dark chasms of time and neglect should be put aside. Brian D. Warner Palmer Divide Observatory 17995 Bakers Farm Rd. Colorado Springs, CO 80908 Mikko Kaasalainen Rolf Nevanlinna Institute P.O. Box 4 (Yliopistonkatu 5, room 714) FIN-00014 University of Helsinki Finland References Hardie, R. H. (1959). “An Improved Method for Measuring Extinction.” Astrophys. J. 130, 663-669. Henden, A. and Kaitchuck, R. (1990). Astronomical Photometry. Willmann-Bell, Inc., Richmond, VA. Wood, F. B. (1963). Macmillan, New York. Photoelectric Astronomy for Amateurs. So that neither goal – more raw lightcurves and curves for shape/axis studies – is neglected, we’re including two lists. The first contains asteroids that have no or poorly established parameters. Note that this time around we’ve included a number with at least preliminary values, some with very long periods. These are challenging, no doubt, but no less important than a passing NEO spinning several times an hour. In fact, they may be more important right now since the slow rotators are, for a large part, the greatest mystery in the study of spin rates. Alan W. Harris Space Science Institute 4603 Orange Knoll Ave. La Canada, CA 91011-3364 Petr Pravec Astronomical Institute CZ-25165 Ondrejov Czech Republic ppravec@asu.cas.cz Spinning “flat hamburgers”, “potatoes”, and “footballs” are often used to describe an asteroid when explaining its lightcurve. Even the human head can give a reasonable approximation to some lightcurves – assuming the person is not bald! The point is that asteroids come in all sorts of shapes and sizes and that it’s becoming increasingly important to determine the shapes and orientation of the spin axis for as many asteroids as possible. A recent review of the known lightcurves and spin axes shows an almost certain influence of the YORP effect on the spin rates and orientations of asteroids less than about 40km in size. The exact shape, or good approximation, of the asteroid is important since the influence of the YORP effect is most powerful when the object is highly irregular in shape. The second list should be of help for those with smaller instruments. They are relatively bright and so should be within easy reach. These objects are only a small number of well done lightcurves away from having their shape and/or spin axis resolved, or at least reasonably known. Those working objects on this list should contact co-author Mikko Kaasalainen to coordinate their efforts with his and to be sure that the object has not since been observed well enough to have been modeled. Important Notes: 1) The periods that are listed should be considered preliminary. Don’t be overly influenced by them and try to force your results to the same or similar values. Let the data dictate the solution, not vice versa. 2) The Declination is actually for when the asteroid is brightest. In most cases, it is about the same for when at opposition. Minor Planet Bulletin 31 (2004) 47 You’ll find a more complete list of lightcurve opportunities for the current and recent quarters on the CALL web site. (http://www.MinorPlanetObserver.com/astlc/default.htm). Be sure to check the link on the CALL site to planned radar observations. Optical observations are often needed to support the radar work. Lightcurve Opportunities # 498 168 203 744 265 566 143 755 1605 738 1109 407 680 863 613 1728 1143 1994 6669 1353 478 2091 2957 159 582 4558 839 227 3089 427 12008 1246 780 1274 426 749 275 954 696 9601 1031 1738 Name Tokio Sibylla Pompeja Aguntina Anna (F) Stereoskopia Adria Quintilla (F) Milankovitch Alagasta Tata Arachne Genoveva Benkoela Ginevra Goethe Link Odysseus Shane Obi Maartje Tergeste Sampo Tatsuo (F) Aemilia Olympia Janesick Valborg Philosophia (F) Oujianquan (F) Galene 1996 TY9 (F) Chaka Armenia Delportia Hippo Malzovia (F) Sapientia Li Leonora 1991 UE3 (F) Arctica Oosterhoff Opposition Date Mag 4 06.2 13.4 4 06.1 12.9 4 06.0 12.6 4 11.2 14.1 3 30.2 13.4 4 14.2 13.3 4 09.2 12.7 4 17.1 13.3 4 19.7 14.5 4 19.5 14.0 4 17.0 14.2 4 16.5 12.8 4 23.9 12.7 5 06.7 13.9 5 09.5 14.1 5 12.1 14.1 5 14.0 15.0 5 18.6 14.9 5 19.2 14.2 5 21.3 14.4 5 21.8 12.3 5 24.8 14.8 5 27.9 13.9 5 30.8 12.8 6 07.0 14.0 5 28.2 14.2 5 26.6 13.5 6 02.2 12.2 6 06.1 14.0 6 06.1 13.4 5 31.1 12.7 6 07.9 13.9 6 13.5 13.8 6 16.2 13.9 6 17.7 12.7 6 20.3 13.2 6 21.2 12.5 6 23.1 13.4 6 26.3 14.0 6 30.9 13.9 6 30.3 14.3 6 30.2 13.7 Dec + 8 - 8 - 9 + 2 -46 - 4 -23 - 8 - 2 - 6 -16 -22 -10 +21 -27 -20 -18 -22 -22 -14 -18 - 7 -22 -14 +20 -27 -43 -37 -16 -28 -34 -38 + 2 -31 -45 -19 -18 -22 -31 -29 + 0 -32 Per Amp >20. >0.36 23.82 >0.30 46.6 >0.10 17. 11. 0.08 13.29 0.15 44. 0.45 16.45 0.63 >12. 25.? 0.11 >0.1 15. 71.3 0.2 0.38 25. 36.0 100. >0.2 >0.6 >0.11 Name Frigga Aurelia Astraea Danby Desiderata Atalante Bathilde Hansa Shaposhnikov Nemausa Patientia Doris Adelheid Papagena Freia Themis Siegena Opposition Date Mag Dec 4 04.3 12.3 -07 4 20.2 10.6 -14 4 28.6 9.8 -05 5 01.3 17.3 -16 5 06.0 9.8 -15 5 10.5 13.8 -40 5 15.2 12.5 -23 5 19.4 11.8 -19 5 25.5 14.5 -23 5 28.7 10.3 -05 5 30.8 11.3 -14 5 31.9 11.6 -13 6 01.7 13.4 -02 6 05.9 11.3 -19 6 09.0 13.3 -21 6 18.3 11.6 -24 6 21.7 12.1 +06 The Minor Planet Bulletin is open to papers on all aspects of minor planet study. Theoretical, observational, historical, review, and other topics from amateur and professional astronomers are welcome. The level of presentation should be such as to be readily understood by most amateur astronomers. The preferred language is English. All observational and theoretical papers will be reviewed by another researcher in the field prior to publication to insure that results are presented clearly and concisely. It is hoped that papers will be published within three months of receipt. However, material submitted by the posted deadline for an issue may or may not appear in that issue, depending on available space and editorial processing. The MPB will not generally publish articles on instrumentation. Persons interested in details of CCD instrumentation should join the International Amateur-Professional Photoelectric Photometry (IAPPP) and subscribe to their journal. Write to: Dr. Arnold M. Heiser, Dyer Observatory, 1000 Oman Drive, Brentwood, TN 37027 (email: heiser@astro.dyer.vanderbilt.edu). The MPB will carry only limited information on asteroid occultations because detailed information on observing these events is given in the Occultation Newsletter published by the International Occultation Timing Association (IOTA). Persons interested in subscribing to this newsletter should write to: Art Lucas. Secretary & Treasurer, 5403 Bluebird Trail, Stillwater, OK 74074 USA (business@occultations.org). Astrometry measurements should be submitted to the IAU Minor Planet Center and are no longer being published or reproduced in the MPB. Manuscript Preparation >20. >0.2 >32. 0.15 >20. 14. >0.05 0.2 51.0 >0.22 Shape/Axis Opportunities # 77 419 5 3415 344 36 441 480 1902 51 451 48 276 471 76 24 386 INSTRUCTIONS FOR AUTHORS Per (h) 9.012 16.709 16.800 2.851 10.77 9.93 10.447 5.324 21.2 7.783 9.727 11.89 6.328 7.113 9.972 8.374 9.763 Amp. 0.07-0.19 0.08 0.10-0.30 0.09-0.14 0.17 0.15-0.17 0.13 0.29 0.42 0.10-0.14 0.05-0.10 0.35 0.07-0.10 0.11-0.13 0.10-0.33 0.09-0.14 0.11 It is strongly preferred that all manuscripts be prepared using the template found at: http://www.minorplanetobserver.com/astlc/ default.htm Manuscripts should be less than 1000 words. Longer manuscripts may be returned for revision or delayed pending available space. For authors not using the template noted above, manuscripts may be submitted electronically as ASCII text or on paper as a typescript. Typescripts should be typed double spaced and consist of the following: a title page giving the names and addresses of all authors (editorial correspondence will be conducted with the first author unless otherwise noted), a brief abstract not exceeding four sentences, the text of the paper, acknowledgments, references, tables, figure captions, and figures. Please compile your manuscripts in this order. For lightcurve articles, authors are encouraged to combine as many objects together in a single article as possible. For general articles, the number of tables plus figures should not exceed two. Tables should be numbered consecutively in Roman numerals, figures in Arabic numerals. We will typeset short tables, if necessary. Longer tables must be submitted in “camera ready” format, suitable for direct publication. Font size should be large enough to allow for clear reproduction within the column dimensions described below. We prefer to receive figures in electronic format, 300 dpi or higher quality, black markings on white. Because of their high reproduction cost, the MPB will not print color figures. Labeling should be large enough to be easily readable when reproduced to fit within the MPB column format. If at all possible, you are strongly encouraged to supply tables and figures at actual size for direct reproduction. Tables and figures intended for direct reproduction to occupy one-half page width should be 8.6 cm wide, or full-page width, 17.8 cm. Size your tables and figures to fit one-half page width whenever possible. Minor Planet Bulletin 31 (2004) 48 Limit the vertical extent of your figures as much as possible. In general they should be 9 cm or less. References should be cited in the text such as Harris and Young (1980) for one or two authors or Bowell et al. (1979) for more than two authors. The reference section should list papers in alphabetical order of the first author’s last name. The reference format for a journal article, book chapter, and book are as follows: 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. (1989). “Photoelectric Observations of Asteroids 3, 24, 60, 261, and 863.” Icarus 77, 171-186. Pravec, P., Harris, A. W., and Michalowski, T. (2002). “Asteroid Rotations.” In Asteroids III (W. F. Bottke, A. Cellino, P. Paolicchi, R. P. Binzel, eds.) pp 113-122. Univ. Arizona Press, Tucson. Warner, B. D. (2003). A Practical Guide to Lightcurve Photometry and Analysis. Bdw Publishing, Colorado Springs, CO. Authors are asked to carefully comply with the above guidelines in order to minimize the time required for editorial tasks. Submission All material submitted for publication in the Minor Planet Bulletin should be sent to the editor: Dr. Richard P. Binzel, MIT 54-410, Cambridge, MA 02139, USA (email: rpb@mit.edu). Authors are encouraged to submit their manuscripts electronically as email attachments or as ASCII text, prepared following the instructions above. Alternatively, your article may be sent by post on diskette (all diskettes must be accompanied by a complete printed copy of all material) or as a typed manuscript. When sending material by post, please include high quality original printed figures and tables that can be directly reproduced. In most cases, proofs of articles will be sent to authors prior to publication. THE MINOR PLANET BULLETIN (ISSN 1052-8091) is the quarterly journal of the Minor Planets Section of the Association of Lunar and Planetary Observers. The Minor Planets Section is directed by its Coordinator, Prof. Frederick Pilcher, Department of Physics, Illinois College, Jacksonville, IL 62650 USA (pilcher@hilltop.ic.edu), assisted by Lawrence Garrett, 206 River Road, Fairfax, VT 05454 USA (Lgasteroid@globalnetisp.net). Richard Kowalski, 7630 Conrad St., Zephyrhills, FL 33544-2729 USA (qho@bitnik. com) is Associate Coordinator for Observation of NEO’s, and Steve Larson, Lunar and Planetary Laboratory, 1629 E. University Blvd., University of Arizona, Tucson, AZ 85721 USA (slarson@lpl.arizona.edu) is Scientific Advisor. The Asteroid Photometry Coordinator is Brian D. Warner, Palmer Divide Observatory, 17995 Bakers Farm Rd., Colorado Springs, CO 80908 USA (brian@MinorPlanetObserver.com). The Minor Planet Bulletin is edited by Dr. Richard P. Binzel, MIT 54-410, Cambridge, MA 02139 USA (rpb@mit.edu) and is produced by Dr. Robert A. Werner, JPL MS 301-150, 4800 Oak Grove Drive, Pasadena, CA 91109 USA (robert.a.werner@jpl.nasa.gov). Derald D. Nye serves as the distributor. The staff of the Minor Planet Section invites MPB subscribers who are not members of our parent organization (Association of Lunar and Planetary Observers – ALPO) to join by communicating with: Matthew L. Will, A.L.P.O. Membership Secretary, P.O. Box 13456, Springfield, IL 627913456 (will008@attglobal.net). The contact for all subscriptions, address changes, etc. is: Mr. Derald D. Nye Minor Planet Bulletin 10385 East Observatory Drive Corona de Tucson, AZ 85641-2309 USA (nye@kw-obsv.org) (Telephone: 520-762-5504) Subscription rates (per year, four issues): Payment by check $14.00 $19.00 North America All other Payment by credit card $15.00 $20.00 To minimize our administrative time, please consider subscribing for two years. Checks or money orders should be in US dollars, drawn on a US bank, and made payable to the “Minor Planet Bulletin.” To pay by credit card, (Visa, Mastercard, or Discover) please send by mail your credit card number, your name exactly as it appears on the card, and the expiration date. Be sure to specify the desired length of your subscription. Credit card charges will be made through “Roadrunner Mkt, Corona AZ.” When sending your subscription order, be sure to include your full mailing address and an email address, if available. The numbers in the upper-right corner of your mailing label indicate the volume and issue number with which your current subscription expires. Articles for submission to the MPB should be sent to the editor. All authors should follow the guidelines given in “Instructions for Authors” in issue 30–4 and also available at http://www.MinorPlanetObserver.com/ astlc/default.htm . Authors with access to Apple Macintosh or IBM-PC compatible computers are strongly encouraged to submit their manuscripts by electronic mail (rpb@mit.edu) or on diskette. Electronic submissions can be formatted either using a Microsoft Word template document available at the web page just given, or else as text-only. A printed version of the file and figures must also be sent. All materials must arrive by the deadline for each issue. We regret that diskettes cannot be returned. Visual photometry observations, positional observations, any type of observation not covered above, and general information requests should be sent to the Coordinator. * * * * * The deadline for the next issue (31-3) is April 15, 2004. The deadline for issue 31-4 is July 15, 2004. Minor Planet Bulletin 31 (2004)