------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 1745 2002 Feb 20 15.06UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK GMH at AST.STAR.RL.AC.UK WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- COMET C/2002 C1 (IKEYA-ZHANG) Brian Marsden, Central Bureau for Astronomical Telegrams, reports that a parabolic orbit for this comet no longer fits the available observations which totalled 144 for the period 2002 Feb 1-14. He also mentions that S. Nakano has suggested this comet may be identical with C/1532 R1 based on results to Feb 10. According to 'Comets, Vagabonds of Space' by David Seargent, Chambers records a daylight comet for 1532, presumably a comet of September or October and of probable magnitude -2 or -3. The perihelion distance was 0.52AU and the absolute magnitude about 2. Donald Yeomans also lists the object of 1532 in his WWW page on 'Great Comets in History'. We stress, however, the link remains tentative. Ephemeris revision (cf TA E-circular 1742): T 2002 Mar 18.9388 TT w 34.57770 ) e 0.99120700 O 93.41560 ) 2000.0 q 0.5072000 A.U. i 28.11100 ) Source: MPEC2002-C111 Positions are geocentric m = 7.5 + 5.0 log R + 10.0 log r Date R.A. (2000) Dec. R r Elong Mag. Motion h m o ' (AU) (AU) o "/hr P.A. 2002 Feb 20.00 0 43.11 -6 53.3 1.313 0.799 37.3 7.1 129 36 21.00 0 45.13 -6 11.0 1.298 0.782 37.0 7.0 131 35 22.00 0 47.17 -5 27.8 1.282 0.766 36.6 6.9 133 35 23.00 0 49.21 -4 43.5 1.266 0.750 36.3 6.8 135 34 24.00 0 51.25 -3 58.2 1.249 0.734 36.0 6.6 138 34 25.00 0 53.30 -3 11.7 1.233 0.719 35.7 6.5 140 33 26.00 0 55.36 -2 24.2 1.216 0.703 35.3 6.4 143 33 27.00 0 57.40 -1 35.4 1.199 0.688 35.0 6.3 145 32 28.00 0 59.45 -0 45.5 1.181 0.673 34.7 6.1 148 31 2002 Mar 1.00 1 1.48 +0 5.7 1.164 0.659 34.5 6.0 150 30 2.00 1 3.49 +0 58.2 1.146 0.645 34.2 5.9 153 30 3.00 1 5.48 +1 52.1 1.127 0.631 33.9 5.8 155 29 4.00 1 7.44 +2 47.3 1.109 0.618 33.6 5.6 157 28 5.00 1 9.37 +3 43.9 1.090 0.605 33.4 5.5 160 27 6.00 1 11.26 +4 41.9 1.072 0.593 33.1 5.4 162 25 7.00 1 13.09 +5 41.4 1.053 0.581 32.9 5.3 165 24 8.00 1 14.86 +6 42.3 1.033 0.570 32.6 5.1 167 23 9.00 1 16.56 +7 44.8 1.014 0.560 32.4 5.0 169 21 10.00 1 18.17 +8 48.7 0.994 0.550 32.2 4.9 172 20 11.00 1 19.69 +9 54.1 0.975 0.542 31.9 4.8 174 18 12.00 1 21.10 +11 1.0 0.955 0.534 31.7 4.7 176 16 13.00 1 22.38 +12 9.4 0.935 0.527 31.5 4.6 178 15 14.00 1 23.53 +13 19.2 0.915 0.521 31.3 4.5 180 13 15.00 1 24.53 +14 30.3 0.895 0.516 31.1 4.4 182 11 16.00 1 25.36 +15 42.8 0.875 0.512 31.0 4.3 185 8 17.00 1 26.01 +16 56.5 0.855 0.509 30.8 4.2 187 6 18.00 1 26.47 +18 11.3 0.836 0.508 30.6 4.2 189 4 19.00 1 26.71 +19 27.3 0.816 0.507 30.5 4.1 191 2 20.00 1 26.73 +20 44.3 0.797 0.508 30.4 4.1 193 359 21.00 1 26.52 +22 2.1 0.778 0.510 30.3 4.0 196 357 22.00 1 26.06 +23 20.8 0.760 0.512 30.3 4.0 198 354 23.00 1 25.35 +24 40.1 0.742 0.516 30.3 4.0 201 352 24.00 1 24.36 +26 0.1 0.724 0.522 30.3 4.0 204 349 25.00 1 23.10 +27 20.5 0.706 0.528 30.4 4.0 207 347 26.00 1 21.55 +28 41.4 0.690 0.535 30.6 4.0 210 345 27.00 1 19.71 +30 2.6 0.673 0.543 30.8 4.0 213 343 28.00 1 17.58 +31 24.0 0.657 0.551 31.0 4.0 216 340 Guy M Hurst