------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 1210 1997 Jul 06 14.28UT 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.demon.co.uk/astronomer ------------------------------------------------------------------- COMET C/1997 N1 (TABUR) The above is the new designation for the comet announced on E1208. Parabolic elements by Brian Marsden from 14 observations July 3-5: T 1997 Aug 15.2470 TT w 345.44800 ) e 1.00000000 O 148.24000 ) 2000.0 q 0.3832200 A.U. i 86.40200 ) Source: IAUC 6694 Positions are geocentric Ephemeris by G.Hurst using EPH.EXE by N.James: m = 9.0 + 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. 1997 July 7.00 5 19.29 -25 30.0 1.193 1.024 54.5 9.5 262 76 8.00 5 26.83 -25 4.3 1.185 1.005 53.6 9.4 265 76 9.00 5 34.42 -24 36.9 1.178 0.985 52.8 9.3 269 75 10.00 5 42.04 -24 7.7 1.171 0.966 51.8 9.2 272 74 11.00 5 49.69 -23 36.7 1.166 0.947 50.9 9.1 275 73 12.00 5 57.34 -23 3.8 1.161 0.928 49.9 9.0 277 72 13.00 6 4.99 -22 29.1 1.157 0.908 48.9 8.9 280 71 14.00 6 12.63 -21 52.6 1.154 0.889 47.8 8.8 282 71 15.00 6 20.25 -21 14.3 1.152 0.869 46.8 8.7 283 70 16.00 6 27.84 -20 34.3 1.150 0.850 45.7 8.6 285 69 17.00 6 35.38 -19 52.6 1.150 0.830 44.5 8.5 286 68 18.00 6 42.87 -19 9.2 1.150 0.811 43.4 8.4 287 67 19.00 6 50.31 -18 24.3 1.151 0.791 42.2 8.3 287 67 20.00 6 57.67 -17 37.8 1.153 0.771 41.0 8.2 287 66 21.00 7 4.95 -16 49.8 1.156 0.752 39.8 8.1 287 65 22.00 7 12.16 -16 0.4 1.160 0.732 38.6 8.0 287 64 23.00 7 19.28 -15 9.6 1.164 0.712 37.4 7.9 287 63 24.00 7 26.30 -14 17.4 1.169 0.693 36.1 7.7 286 63 25.00 7 33.23 -13 24.1 1.175 0.673 34.8 7.6 285 62 26.00 7 40.05 -12 29.4 1.182 0.654 33.6 7.5 284 61 27.00 7 46.78 -11 33.7 1.189 0.635 32.2 7.4 283 60 28.00 7 53.40 -10 36.7 1.197 0.616 30.9 7.3 282 59 29.00 7 59.92 -9 38.6 1.206 0.597 29.6 7.2 281 59 30.00 8 6.33 -8 39.5 1.215 0.578 28.3 7.0 279 58 31.00 8 12.64 -7 39.2 1.225 0.559 26.9 6.9 278 57 Martin Mobberley, Assistant Editor, comments as follows: Comet Tabur is currently a southern hemisphere object, totally unobservable from the UK. It is currently in Lepus and moves into Canis Major by mid-July, passing a few degrees south of Sirius on the 18th/19th (and some ten degrees south of the fifth mag Hale-Bopp). The new comet may be around 8th mag by this time, if Tabur's discovery estimate of mag 10 is accurate. >From late July through to early September it will be unobservable from both hemispheres as perihelion occurs when the earth and the comet are on opposite sides of the Sun (the elongation is only 3 degrees on August 19th), the worst possible observational circumstance! In mid-September the comet becomes visible from the UK, at around ninth mag, low in the west-northwest twilight and some thirty-five degrees due north of the Sun. During this time it will be border-line circumpolar (from 52N) whilst passing through Canes Venatica. Unfortunately, it will be well past it's best by then, at around 9th or 10th magnitude. However, with r<1.0 up to late September, CCD images should reveal a few arc-minutes of tail. The comet stays at around +38 Dec until late October, drifting eastward through Bootes and Corona Borealis but fading to mag 13 by early November. Guy M Hurst