THE ASTRONOMER Electronic Circular No 639 1992 May 21 20.09UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England. Telephone/FAX(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 ------------------------------------------------------------------- EDITORIAL ABSENCE I shall be away and not contactable direct between Saturday May 23 06.00UT and Monday May 25 when I return about 21.00UT. During this time urgent messages will be relayed by Martin Mobberley. Please send to my usual mailboxes but with a copy to Martin at either: 10087:YQQ594 (Telecom Gold) or cbs%uk.ac.sussex.cluster::mafa2 (JANET). COMET SPACEWATCH (1992h) Preliminary parabolic orbital elements by B. G. Marsden, Center for Astrophysics, from 13 observations May 1-4: T = 1993 Sept. 7.648 TT Peri. = 80.639 Node = 203.265 2000.0 q = 3.15511 AU Incl. = 125.125 IAUC 5513 The comet is fading below mag 18. HV VIRGINIS P. Szkody and D. Ingram, University of Washington, report: "Time-resolved CCD photometry of the very-large-outburst-amplitude dwarf nova HV Vir on Apr. 30.34-30.42 and on May 1.20-1.25 and 1.34-1.42 UT with the 1.8-m ARC telescope indicate superhumps of 0.2 mag amplitude and period of 84.1 +/- 0.4 min. The V magnitude was about 13.4 and indicates that the object is declining from out- burst. Since the superhump period is a few percent longer than the orbital period, HV Vir increases the correlation of large-outburst amplitude with orbital periods below the period gap for high galac- tic latitude dwarf novae (Howell and Szkody 1990, Ap.J. 356, 623); 11 of the 12 with known orbital periods are now below the gap." IAUC 5516 SUPERNOVAE 1992W, 1992X, 1992Y Jean Mueller reports her discovery of three supernovae on plates taken with the 1.2-m Oschin Telescope in the course of the second Palomar Sky Survey. SN 1992W was at mag about 18 on a red plate taken by J. D. Mendenhall and Mueller on Apr. 28; the supernova is located 24" west and 32" north of the center of MCG +08-23-096 (R.A. = 12h48m.0, Decl. = +48 22', equinox 1950.0). SN 1992X was at also mag about 18 on a red plate taken by C. Brewer and Mendenhall on May 2; the supernova is located 2" west and 7" south of the center of MCG +06-32-024 (R.A. = 14h22m09s, Decl. = +35 22'.0). W. Sargent and T. Small confirmed SNe 1992W and 1992X with spectrograms obtained May 9 at the Hale 5-m telescope (+ double spectrograph). SN 1992Y in NGC 3527 (R.A. = 11h04m.5, Decl. = +28 48') was at mag 18.5-19 on a blue plate taken May 2 by Brewer and Mendenhall. SN 1992Y is located 13" east and 6" south of the galaxy's nucleus; no image is present at this location on prints from the original Palomar Sky Survey. IAUC 5517 NOVA CYGNI 1992 Recent results suggest that this nova has stopped fading. The apparent standstill appears to have started around 1992 Apr 27 and the nova remains near magnitude 8.3 visual in the latest estimates made on May 20 Guy M Hurst