Circular No. 5411 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Telephone 617-495-7244/7440/7444 (for emergency use only) TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505 MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN 1991 VL Further precise positions, including prediscovery positions, have been reported from films taken with the 0.46-m Palomar Schmidt by teams led by E. M. Shoemaker (with C. S. Shoemaker, D. H. Levy and T. King) and E. Helin (with K. Lawrence, P. Rose and R. Bambery): 1991 UT R.A. (2000) Decl. B Observer Oct. 5.39861 2 05 23.21 +29 00 39.9 17.9 Shoemaker 5.43733 2 05 19.51 +29 00 40.3 " 10.43021 1 56 55.93 +28 55 55.3 17 Helin 10.45313 1 56 53.57 +28 55 52.0 " 12.43264 1 53 13.48 +28 51 20.3 " 12.45764 1 53 10.66 +28 51 16.3 " Dec. 1.10851 0 10 29.80 +18 36 52.7 17.0 Shoemaker 1.14913 0 10 26.64 +18 36 14.8 " 3.10069 0 08 07.04 +18 05 39.4 " 3.13351 0 08 04.69 +18 05 09.4 " Orbital elements from 13 observations Oct. 5-Dec. 3: T = 1992 Mar. 13.9688 TT Peri. = 226.3099 e = 0.771515 Node = 310.8118 2000.0 q = 0.419078 AU Incl. = 9.1955 a = 1.834162 AU n = 0.3967781 P = 2.484 years 1991/92 R. A. (2000) Decl. Delta r Elong. Phase V Dec. 20 23 56.75 +14 23.9 1.029 1.510 97.2 40.3 16.5 30 23 56.64 +12 53.7 1.042 1.390 86.6 44.9 16.5 Jan. 9 0 00.53 +11 51.7 1.044 1.264 77.1 49.3 16.4 19 0 07.63 +11 11.6 1.028 1.130 68.3 54.0 16.3 29 0 17.03 +10 43.2 0.989 0.988 60.1 59.8 16.1 Feb. 8 0 27.46 +10 09.9 0.920 0.839 52.0 68.0 15.8 18 0 35.99 + 8 56.7 0.820 0.685 43.3 81.5 15.6 28 0 34.61 + 5 39.0 0.693 0.539 31.5 106.4 15.8 PERIODIC COMET SHOEMAKER-LEVY 6 (1991b1) Total visual magnitude estimate by A. Hale, Las Cruces, NM (0.41-m reflector): Dec. 7.20 UT, 12.2. 1991 December 24 Brian G. Marsden