------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 1177 1997 Mar 22 18.31UT 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 55P/1997 E1 (TEMPEL-TUTTLE) O. R. Hainaut, University of Hawaii, reports his measurements of the recovery images of the comet associated with the Leonid meteors, as follows: 1997 UT R.A. (2000) Decl. m2 Observer Mar. 4.62838 13 43 12.63 + 4 43 37.7 22.5 Meech 4.637 13 43 12.31 + 4 43 41.7 " 4.64876 13 43 11.57 + 4 43 49.0 " 4.65752 13 43 11.07 + 4 43 54.4 " 7.3108 13 40 40.80 + 5 10 45.3 22 Martin K. J. Meech, O. R. Hainaut and J. Bauer (Mauna Kea). Keck II 10-m reflector + LRIS CCD. Some interference from clouds, but comet clearly visible as a point source. No coma; image profile similar to stars. Seeing 0".8. Magnitude is crude R estimate using 5" diaphragm. Brian Marsden adds: Two recent predictions for comet 55P/Tempel-Tuttle have been made using the observations in 1865-1866, supplemented by the very scanty data from 1366, 1699 and 1965, the comet having been recovered on that last occasion following an insightful prediction by J. Schubart (IAUC 1907, 1926 and 1979). The prediction by S. Nakano and I. Hasegawa (MPC 27288), giving T = 1998 Feb. 28.079 (at epoch 1998 Mar. 8), requires correction by Delta T about -0.14 day; that by D. K. Yeomans et al. (1996, Icarus 124, 407), giving T = 1998 Feb. 28.091, requires correction by Delta T about -0.06 day. For the computation of the following orbital elements, fitted to the nine observations in 1965 and 1997, the Yeomans value of e was assumed: Epoch = 1998 Mar. 8.0 TT T = 1998 Feb. 27.977 TT Peri. = 172.484 e = 0.90551 Node = 235.251 2000.0 q = 0.97657 AU Incl. = 162.485 a = 10.33467 AU n = 0.029666 P = 33.22 years Ephemeris by G.Hurst using EPH.EXE by Nick James. The Mag values relate to m2: Date R.A. (2000) Dec. R r Elong Mag. Motion h m o ' (AU) (AU) o "/hr P.A. 1997 Mar 13.00 13 34.79 +6 10.8 3.490 4.375 149.3 22.4 49 303 23.00 13 22.78 +8 2.3 3.338 4.286 159.5 22.2 56 301 1997 Apr 2.00 13 9.00 +9 56.7 3.226 4.197 164.1 22.1 61 298 12.00 12 54.03 +11 47.3 3.157 4.106 158.4 21.9 62 295 22.00 12 38.67 +13 27.1 3.130 4.015 147.5 21.8 60 293 COMET C/1995 O1 HALE-BOPP We continue to send regular reports of observations to the professional group of astronomers headed by Richard West. He comments that Mark Kidger calculates the absolute magnitude of the comet is now steady at approximately -0.8, the third brightest absolute magnitude recorded since the year 1400. Comet Sarabat of 1729 (absolute magnitude -3.0) and the Comet of 1577 (-1.8) were intrinsically much brighter, while Comet De Cheseaux of 1747 (not the 6 tailed comet) had an absolute magnitude of -0.5. These three comets and Hale-Bopp are the only ones known to have had a negative absolute magnitude. Guy M Hurst