------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2388 2007 Oct 24 13.36UT 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 17P/HOLMES Further to TA E-Circular 2387 issued earlier today, Mark Kidger has submitted a further report: Observations by Juan Antonio Henríquez Santana (MPC J51) show that a major outburst of Comet 17P/Holmes has taken place. Photometry taken during the night of 2007 October 23/24 show that the comet is some 9 magnitudes brighter than on 2007 Oct 22 in a 10" aperture and that the comet was brightening by approximately 0.5 magnitudes/h in a 10" aperture over the course of 6 hours. The outburst has been confirmed by Gustavo Muler at MPC J47 and by Ramón Naves and Montse Campàs at MPC 213. 17P/Holmes had an outburst to approximately magnitude 4 in 1892, but has since been very faint and was lost from 1906 to 1964. Measured R magnitudes in a 10" square aperture are as follows: 2007 Oct 24.067, 8.4 2007 Oct 24.100, 8.0 2007 Oct 24.136, 7.3 Images taken by Gustavo Muler on October 22 show normal brightness. This outburst is evidently still in a very early phase and the bright, inner coma is almost stellar. Almost all the light is concentrated in the inner 20". A preliminary pair of "before" and "after" images can be found at http://astrosurf.com/comets/cometas/17p/imagenes/17p.html. Martin Nicholson, Daventry, UK but observing remotely from New Mexico has reported that the comet has reached approximately magnitude 4 on Oct 24 at 11.32UT. The observation was secured with a Takahashi Epsilon 250mm F/3.8 astrograph and an ST-8XE CCD camera mounted on a Paramount GT1100ME mount. The observatory is at 7300 ft. (2225 meters) elevation. Ernesto Guido and Giovanni Sostero, Italy but also observing from New Mexico have imaged the comet at 07h30m and 09h00m (UT?) clearly showing increased brightness and coma diameter between the two exposure times. SATELLITES OF SATURN The IAU Working Group for Planetary System Nomenclature has approved new designations and names of satellites of Saturn as announced on IAUC 8873: Saturn XLIX Anthe = S/2007 S 4 IAUC 8857 Saturn L Jarnsaxa = S/2006 S 6 IAUC 8727 Saturn LI Greip = S/2006 S 4 IAUC 8727 Saturn LII Tarqeq = S/2007 S 1 IAUC 8836 SUPERNOVAE 2007jy-2007kb The Sloan Digital Sky Survey (SDSS) II collaboration, report on CBET 1081 the discovery of four supernovae: SN Discov. R.A. (2000.0) Decl. Mag. z Est Type Date UT Peak Date 2007jy Sep. 3 20 51 21.43 + 0 23 57.8 20.7 0.18 Sep.4 Ib? 2007jz Sep. 5 1 23 56.01 + 1 15 18.0 21.7 0.22 Sep.15 Ia 2007ka Sep. 5 1 21 22.70 - 0 00 53.3 21.1 0.22 Sep.12 Ia 2007kb Sep. 13 20 52 24.71 + 0 16 39.6 21.4 0.14 Sep.15 Ia SUPERNOVA 2007kc IN UGC 8400 Discovery by Mirko Villi of a possible supernova (CBET 1082): SN 2006 UT R.A. (2000.0) Decl. Mag. Offset 2007kc Sep 21.78 13 21 34.92 +42 16 50.0 15.8 10" W, 4" S Guy M Hurst