THE ASTRONOMER Electronic Circular No 532 1991 June 18 20.32UT 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 LEVY (1991q) Preliminary parabolic orbital elements by S. Nakano, Sumoto, Japan, from 6 observations, June 14-18: T = 1991 July 8.168 ET Peri. = 41.311 Node = 329.824 1950.0 q = 0.99533 AU Incl. = 19.361 Ephemeris by Hurst using a program developed by N.James: m = 7.5 + 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 June 18.00 1 58.68 +16 7.0 1.295 1.054 52.6 8.3 198 56 19.00 2 3.28 +16 50.9 1.295 1.048 52.3 8.3 198 57 20.00 2 7.90 +17 34.5 1.296 1.043 51.9 8.2 198 57 21.00 2 12.56 +18 17.5 1.296 1.038 51.6 8.2 198 57 22.00 2 17.24 +19 0.1 1.297 1.033 51.3 8.2 197 58 23.00 2 21.96 +19 42.1 1.299 1.029 51.0 8.2 197 58 24.00 2 26.70 +20 23.6 1.300 1.025 50.7 8.2 196 58 25.00 2 31.47 +21 4.5 1.302 1.021 50.4 8.2 196 59 26.00 2 36.26 +21 44.7 1.305 1.017 50.1 8.2 195 59 27.00 2 41.09 +22 24.2 1.307 1.014 49.8 8.1 194 60 28.00 2 45.94 +23 3.1 1.310 1.011 49.5 8.1 193 60 29.00 2 50.81 +23 41.2 1.313 1.008 49.3 8.1 193 61 30.00 2 55.71 +24 18.6 1.317 1.005 49.0 8.1 192 61 1991 July 1.00 3 0.63 +24 55.1 1.321 1.003 48.7 8.1 191 62 2.00 3 5.57 +25 30.9 1.325 1.001 48.5 8.1 189 62 3.00 3 10.53 +26 5.8 1.329 0.999 48.2 8.1 188 63 4.00 3 15.51 +26 39.8 1.334 0.998 48.0 8.1 187 63 5.00 3 20.50 +27 13.0 1.338 0.997 47.7 8.1 186 64 6.00 3 25.51 +27 45.2 1.343 0.996 47.5 8.1 185 64 7.00 3 30.53 +28 16.6 1.349 0.996 47.3 8.1 183 65 8.00 3 35.57 +28 47.0 1.354 0.995 47.0 8.1 182 66 9.00 3 40.61 +29 16.5 1.360 0.995 46.8 8.1 180 66 10.00 3 45.66 +29 45.0 1.366 0.996 46.6 8.2 179 67 11.00 3 50.71 +30 12.5 1.372 0.997 46.4 8.2 177 68 12.00 3 55.77 +30 39.1 1.378 0.998 46.3 8.2 176 68 13.00 4 0.83 +31 4.7 1.385 0.999 46.1 8.2 174 69 14.00 4 5.89 +31 29.3 1.391 1.000 45.9 8.2 173 69 15.00 4 10.94 +31 53.0 1.398 1.002 45.8 8.2 171 70 16.00 4 15.99 +32 15.6 1.405 1.004 45.6 8.3 169 71 17.00 4 21.03 +32 37.3 1.412 1.007 45.5 8.3 168 72 S. Larson, D. Levy, and T. Spahr, University of Arizona, report that, when observed with the Catalina 1.5-m reflector on June 18.45 UT, the comet exhibited ion streamers, a dust fan, and one or perhaps two dust envelopes. A spectrum shows CN, C2, C3, H2O+, and possibly NH2. Total visual magnitude estimates: June 16.46 UT, 8.7 (C. S.Morris, Pine Mountain Club, CA, 20x80 binoculars); 16.83, 8.3 (D. A. J. Seargent, The Entrance, N.S.W., 15x80 binoculars); 17.45, 7.6 (D.H. Levy, Tucson, AZ, 0.41-m reflector; 3' sunward fan); 17.86, 8.5 (A. Pearce, Scarborough, W.A., 20x80 binoculars). IAUC 5293 (In part) Guy M Hurst