THE ASTRONOMER Electronic Circular No 520 1991 May 09 19.10UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP, England. Telephone: (0256)471074 Int:+44256471074 Telex: 9312111261 Answerback: TA G JANET BOXES: GMH at UK.AC.CAM.ASTRONOMY.STARLINK or GUYH at UK.AC.SUSSEX.CLUSTER TELECOM GOLD: 10074:MIK2885 PRESTEL 256471074 ------------------------------------------------------------------- SUPERNOVA 1991V IN IC 4508 J. Mueller reports her discovery of an apparent supernova (mag about 18.5) in IC 4508 (R.A. = 14h45m.7, Decl. = +31 59', equinox 1950.0) on a red plate taken Apr. 17 UT by C. Brewer and herself with the 1.2-m Oschin Telescope in the course of the second Palomar Sky Survey. B. Leibundgut, Center for Astrophysics, observing with the 1.2-m telescope at Mt. Hopkins on Apr. 21.4 UT, confirms the existence of SN 1991V, which is 13".5 south of the galaxy's center. IAUC 5258 SUPERNOVA 1991W IN IC 4425 Mueller also reports her discovery of an apparent supernova (mag about 18.5) in IC 4425 (R.A. = 14h24m.5, Decl. = +27 25') on the same plate upon which she found SN 1991V (above). Leibundgut, observing as above, notes that SN 1991W is 0".5 west and 26".1 north of the centre of IC 4425. IAUC 5258 SUPERNOVA 1991X IN NGC 4902 (cf E519) R. H. McNaught, Anglo-Australian Observatory, e-mails the following precise position for the supernova from an exposure by him with the Uppsala Southern Schmidt on May 05.58 UT; R.A. = 12h58m22s.55, Decl. = -14 14'29".8 (equinox 1950.0), uncertainty 0".5 in RA, 0".3 in Decl. Offsets from the nucleus are 13.9" east, 10.7" north. A nearby star of mag 13 is at R.A. 12h58m14s.10, Decl. = -14 16'12".3 The supernova is mag 14.1 (unfiltered Tech. Pan film) and is situated just on the edge of the bar and inside the ring. In response to a telephone alert by the Editor to Mark Kidger in Tenerife, he confirms that the new object has been recorded. The first was secured via tv camera using the 1.55-m Carlos Sanchez Telescope on May 5.906 when the observers were Inma Vidal, Victor Gonzalez and Mark Kidger. It was later also seen visually with the 0.50-m Mons Telescope at x170 at about mag 13.5 by Ricard Casas, Jorge Gonzalez, Alberto Darias, Victor Gonzalez and Mark Kidger. SUPERNOVA 1991Y IN ANONYMOUS GALAXY J. Mueller reports her discovery of an apparent supernova (mag about 19) in a galaxy located at R.A. = 17h13m.7, Decl. = +57 22' (equinox 1950.0) on a blue plate taken Apr. 17 UT by C. Brewer and herself with the 1.2-m Oschin Telescope in the course of the second Palomar Sky Survey. The object is located 7" north of the galaxy centre. IAUC 5259 CH UMA H.Dahle and B.Granslo, Norway, report an outburst of CH UMa as follows: 1991 May 4.94UT, 12.7 (Dahle); 5.02, 12.1 (Granslo). Further estimates: May 5.91, 12.1 (M.Gainsford); 5.94, 12.1 (M.Westlund); 5.99, 11.9 (H.Bengtsson) Guy M Hurst