------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 861 1994 July 19 21.20UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England. Telephone/FAX(0256)471074 Int:+44256471074 INTERNET: GMH at AST.STAR.RL.AC.UK or GMH at GXVG.AST.CAM.AC.UK ------------------------------------------------------------------- PERIODIC COMET SHOEMAKER-LEVY 9 (1993e)/COLLISION WITH JUPITER Fragment C Brian Manning, Stakenbridge, UK reports a probable visual observation of the spot left by the impact of Fragment C. It was seen a little west of the central meridian and almost due south of the shadow transit spot of Io. It was observed on 1994 July 17 and was best seen between 20.00-20.15UT. Instrument 0.26-m reflector x150. The spot was very small and not easily seen. Andy Stephens, Bristol, UK also reports seeing a spot visually on July 17 between 20.21-20.42UT with a 0.254-m SC x189 (no filter). It was easier in daylight and twilight but more difficult when the planet was in a darker sky. The patch was not so intense as the shadow transit (presumed Io? Editor). John Sanford, Costa Mesa, California, USA has faxed a report indicating he has detected two spots on July 18 at 05.00UT using a 0.30-m Ritchey-Chretien. The spots (A and C-Ed?) imaged dark with integrated light and a Starlight Xpress CCD camera. About one second integrations were required at the image scale used with Jupiter taking up about 0.5 of the frame with 3m focal length plus 3x telextender negative lens. Fragment F Further reports, received in part via the SL9 message centre, indicate considerable confusion concerning the detection of the impact of fragment F = 16. This had been predicted to occur 95 percent of a jovian rotation after the E impact, but because the F prediction was early this impact point almost coincided with the E impact point, which was still very active. Nevertheless, it appears that the plume from the F impact was observed at the European Southern Observatory, but only at wavelengths of 5-12 microns. B. Mosser, T. Livengood and H. U. Haufl made the detection on July 18.060 UT, and the plume remained at the limb for more than 20 min. IAUC 6026 Fragment G As expected, the impact of fragment G = 15 was the most spectacular so far, and the first report received was that from H. Nguyen at the South Pole. The University of Chicago's South Pole Infrared Explorer (SPIREX), a 0.60-m telescope operating mainly at 2.36 microns, reported this event on July 18.320 UT. CASPIR 2.34-micron images and IRIS K-grism cubes showed an initial flash on July 18.315 (attributed to fragment G2 = 15b), half as bright as the C-impact site, brightening by about a factor of four on July 18.316 and then stable until 18.319, at which time the G (or G1 = 15a) impact saturated the detectors and produced brilliant diffraction spikes. After July 18.340 the G impact site had decreased in brightness in K to about four times that of the C impact site, but it was detectable in IRIS bands from J to M, as well as in the visible. S. Nakano, Sumoto, Japan, communicates that many amateur astronomers, some using telescopes of aperture only 0.10 m, have visually detected the G impact site; according to A. Nakamura and K. Ito the region was larger than the Great Red Spot and very dark, with a wave to the west like that of site A. IAUC 6026 Guy M Hurst --- 00021 --- Date: Wed, 20 Jul 1994 21:43:09 +0100 (BST)