------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 3069 2015 Mar 31 09.56UT 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 Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- COMET C/2015 F4 (JACQUES) C. Jacques, Brazil, reports his discovery of a comet on CCD images taken by E. Pimentel, J. Barros, and himself with a 0.28-m f/2.2 astrograph at the SONEAR Observatory, Oliveira, Brazil; the comet showed a condensed coma 8" in diameter: 2015 UT R.A. (2000) Decl. Mag. Observer Mar. 27.21144 19 43 13.58 -45 15 48.8 16.2 Jacques 27.22982 19 43 15.44 -45 15 39.5 16.6 " Fifteen stacked 60-s follow-up images taken remotely by Jacques et al. with an iTelescope 0.70-m f/6.6 astrograph at Siding Spring on Mar. 27.8 UT show a coma of diameter 8" with a tiny tail 17" long in p.a. 238 deg. After the comet was posted on the Minor Planet Center's PCCP webpage, other CCD astrometrists have commented on the object's cometary appearance. E. Guido and N. Howes stacked fourteen 60-s exposures taken remotely with an iTelescope 0.43-m f/6.8 astrograph at Siding Spring on Mar. 27.7, which show a sharp central condensation surrounded by a coma about 8" in diameter and a tail about 15" long in p.a. 237 deg. E. Bryssinck, Belgium, advises CBET that twelve stacked 120-s images taken remotely with a Tzec Maun 0.15-m f/7.3 refractor at Siding Spring on Mar. 28.74-28.77 show the comet to be strongly condensed with almost no coma visible (size about 13"; red magnitude 15.8) but with a clear tail about 48" long toward the southwest in p.a. 237 degrees. Gareth Williams, Minor Planet Center reports on M.P.E.C. 2015-F159: Orbital elements: C/2015 F4 (Jacques) T 2015 Aug. 8.20155 TT MPCW q 1.7349640 (2000.0) P Q Peri. 31.63809 +0.58568796 +0.39334211 Node 286.99653 -0.80717575 +0.36258886 e 1.0 Incl. 47.82222 +0.07373552 +0.84487354 >From 66 observations 2015 Mar. 27-30. Ephemeris: Date TT R. A. (2000) Decl. Delta r Elong. m1 2015 03 30 19 48 16.7 -44 48 00 2.3787 2.4003 79.21 16.7 2015 03 31 19 50 03.6 -44 37 42 2.3593 2.3920 79.73 16.7 2015 04 01 19 51 49.6 -44 27 15 2.3399 2.3838 80.34 16.6 2015 04 07 20 02 03.3 -43 20 54 2.2234 2.3349 83.6 16.4 2015 04 15 20 14 38.9 -41 42 09 2.0684 2.2712 88.3 16.1 2015 04 30 20 34 30.2 -37 59 27 1.7818 2.1573 97.4 15.6 Guy M Hurst