THE ASTRONOMER Electronic Circular No 529 1991 June 8 9.06UT 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 ------------------------------------------------------------------- 3C 345 F.Makino in Japan has reported that X-ray observation with the Ginga satellite of this quasar on 1991 May 25 shows the flux to have doubled since 1989 Apr 27. We are asked to monitor this object optically, which in fact is in accordance with earlier requests by Dr.Mark Kidger in Tenerife (cf E494,495). The latest results from Gary Poyner in Birmingham for May are: May 1.97, [14.3; 5.96, [15.2; 9.03, [14.3; 11.98, [15.2; 14.96, [14.3; 25.01, [14.3. Please e-mail your results regularly even if negative. If anyone requires a chart please e-mail me. SUPERNOVA 1991ae IN MCG +11-19-018 J. Mueller reports her discovery of a supernova 2" west and 8" north of the nucleus of the galaxy MCG +11-19-018 (R.A. = 15 48.4, Decl. = +68 15, equinox 1950.0). The object was at B approx. 18 on a plate taken on May 17 by C. Brewer, J. D. Mendenhall and herself with the 1.2-m Oschin Telescope in the course of the Second Palomar Sky Survey. A spectrum obtained by W. Sargent and M. Strauss with the 5-m Hale Telescope (+ double spectrograph) on June 6 shows strong H Alpha and H Beta emission and He I 587.6-nm emission, indicating a peculiar type II supernova; the object was then at mag approx. 17. IAUC 5282 SUPERNOVA 1991af IN ANONYMOUS GALAXY J. Mueller also reports her discovery, from a similar plate taken on May 19, of a supernova in an anonymous galaxy at R.A. = 17 25.1, Decl. = +29 31 (equinox 1950.0). The SN is 6".7 east and 3".3 south of the centre of the galaxy and had B approx. 18.5 mag. A June 6 spectrum obtained as above indicates that this is a type II supernova. IAUC 5282 PERIODIC COMET D'ARREST = COMET LA HIRE (1678) Although the possibility of the identity of P/d'Arrest with a comet observed by La Hire in 1678 was suggested shortly after its 1851 discovery (Valz 1851, Comptes Rend. No. 2, p. 155) and promptly forgotten, this has recently been independently considered by A. Carusi, and G. B. Valsecchi, Istituto Astrofisica Spaziale, Rome, and L. Kresak and M. Kresakova, Slovak Astronomical Institute, Bratislava, and proven to be correct. Although eight approaches within 0.5 AU of Jupiter during the 26 revolutions 1678-1851 complicate the linkage, Carusi et al. have ascertained that the nongravitational effects on the comet, while relatively large, seem to be extraordinarily stable. The following orbital elements established by them for the 1678 epoch satisfy three of La Hire's four observations within 0.2 deg: T = 1678 Aug. 23.395 ET, Peri. = 159.377, Node = 168.939, Incl. = 2.811 (equinox 1950.0), q = 1.16285 AU, e = 0.67008. IAUC 5283 Guy M Hurst