THE ASTRONOMER Electronic Circular No 498 1991 Mar 24 16.00UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP, England. Telephone: (0256)471074 Int:+44256471074 Telex: 9312111261 Answerback: TA G JANET BOXES: GMH at UK.AC.CAM.ASTRONOMY.STARLINK or GUYH at UK.AC.SUSSEX.CLUSTER TELECOM GOLD: 10074:MIK2885 PRESTEL 256471074 ------------------------------------------------------------------- COMET HELIN-LAWRENCE (1991l) Eleanor F. Helin and Kenneth J. Lawrence report their discovery of a comet, as follows: 1991 UT R.A. (1950) Decl. m1 Observer Mar. 17.40191 13 32 10.92 + 8 52 13.4 15 Helin 17.42483 13 32 08.94 + 8 52 15.7 " 19.69248 13 29 19.55 + 8 56 41.2 15 McNaught E. Helin, K. Lawrence, and P. Rose (Palomar). 0.46-m Schmidt tele- scope films. Measured by Lawrence. Comet image extremely dense, with a tail fanning to the north-northeast. IAUC 5213 Preliminary parabolic elements from 10 observations Mar. 17-21: T = 1992 Feb. 19.166 ET Peri. = 262.890 Node = 9.648 1950.0 q = 1.88148 AU Incl. = 102.503 IAUC 5215 Ephemeris by Hurst using a program by N.James: m = 4.5 + 5.0 log R + 10.0 log r Date R.A. (1950) Dec. R r Elong Mag. Motion h m o ' (AU) (AU) o "/hr P.A. 1991 Mar 24.00 13 23.68 +9 4.3 3.255 4.199 158.8 13.3 50 275 25.00 13 22.32 +9 5.9 3.241 4.190 159.6 13.3 51 275 26.00 13 20.94 +9 7.5 3.228 4.182 160.5 13.3 51 274 27.00 13 19.54 +9 9.0 3.216 4.173 161.2 13.2 52 274 28.00 13 18.13 +9 10.4 3.204 4.164 162.0 13.2 53 274 29.00 13 16.71 +9 11.8 3.192 4.155 162.6 13.2 53 274 30.00 13 15.26 +9 13.1 3.180 4.146 163.2 13.2 54 273 31.00 13 13.81 +9 14.3 3.169 4.137 163.7 13.2 54 273 1991 Apr 1.00 13 12.34 +9 15.4 3.159 4.129 164.1 13.2 55 273 2.00 13 10.85 +9 16.4 3.148 4.120 164.4 13.1 55 273 3.00 13 9.36 +9 17.4 3.138 4.111 164.6 13.1 56 272 4.00 13 7.85 +9 18.2 3.129 4.102 164.7 13.1 56 272 5.00 13 6.33 +9 19.0 3.120 4.093 164.7 13.1 56 272 6.00 13 4.80 +9 19.6 3.111 4.084 164.6 13.1 57 272 7.00 13 3.26 +9 20.2 3.103 4.076 164.3 13.1 57 271 8.00 13 1.71 +9 20.6 3.095 4.067 163.9 13.0 57 271 9.00 13 0.16 +9 21.0 3.088 4.058 163.5 13.0 58 271 10.00 12 58.59 +9 21.2 3.081 4.049 162.9 13.0 58 270 11.00 12 57.03 +9 21.3 3.074 4.040 162.3 13.0 58 270 12.00 12 55.45 +9 21.2 3.068 4.031 161.6 13.0 58 270 13.00 12 53.88 +9 21.1 3.062 4.023 160.8 13.0 58 269 14.00 12 52.30 +9 20.8 3.057 4.014 160.0 13.0 59 269 15.00 12 50.71 +9 20.4 3.052 4.005 159.1 12.9 59 269 16.00 12 49.13 +9 19.8 3.047 3.996 158.2 12.9 59 269 17.00 12 47.55 +9 19.2 3.043 3.987 157.2 12.9 59 268 18.00 12 45.96 +9 18.4 3.039 3.978 156.2 12.9 59 268 The comet could reach mag 8 in 1992 January when it will be located in the southern sky. E-INDEX Roger Pickard has re-joined TELECOM GOLD. His mailbox is: 10074:MIK3229 Guy M Hurst