THE ASTRONOMER Electronic Circular No 506 1991 April 6 09.55UT 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 ------------------------------------------------------------------- NOVA CENTAURI 1991 N. Suntzeff, Cerro Tololo Interamerican Observatory, reports that a CCD spectrogram obtained by M. Hamuy at the CTIO 1.5-m telescope on Apr. 3.085 UT confirms that the object reported by Liller (cfE505) is a nova. R. H. McNaught, University of Adelaide, reports the following precise position measured from an Uppsala Southern Schmidt telescope film: R.A. = 13h46m37s.13, Decl. = -62 54'00".0 (equinox 1950.0). This position represents an empty field on the SERC J, R, and I and ESO B and R surveys, indicating a magnitude at quiescence of fainter than mpg = 22.5. The nearest star on the surveys is of mag 19 with end figures 37s.38, 53'57".7. No nearby star shows any noticeable proper motion by intercomparison of the 9 survey films examined. Field stars measured on the Uppsala nova film and the 1976 U.K. Schmidt Telescope photograph agree to 0".3. A nearby star of similar brightness has end figures 39s.94, 53'52".2. IAUC 5231 Rob McNaught, Australia, e-mails that P.Camilleri, Victoria, reports magnitude estimates from T-Max 400 exposures with a 200mm lens: Mar 11, [13; 22.66, 12.5. Preliminary estimates by McNaught: Apr 3.81, 11.4; 4.49, 11.5. V854 CENTAURI Rob McNaught e-mails that this R-CrB type variable continues to fade (cf E494) reaching 13.2 on Apr 4.49UT. NOVA HERCULIS 1991 Further magnitude estimates: 1991 Mar 26.14UT, 7.2 (O.Midtskogen, Norway); 27.05, 8.2: (B.Granslo, Norway); 29.08, 8.5 (Midtskogen); 31.01, 9.0: (H.Dahle, Norway); 31.12, 9.0 (Midtskogen); Apr 3.09UT, 10.6pv (D.Buczynski, Conder Brow Observatory); 3.99, 11.0 (Granslo); 4.01UT, 10.8pv (Buczynski) ; 6.07, 10.9 (W.Worraker, Didcot). Mark Kidger e-mails calculated decay rates: March 25.19-26.19 2.05 mag/day 26.19-30.19 0.35 mag/day 30.19- 0.52 mag/day (when report sent Apr 4) He mentions a probable max near V=5.0 and that it reached V=8.0 at Mar 27.79UT, and therefore t3=2.8 days, effectively making it the fastest initial decline recorded, even greater than V1500 Cyg. A fuller analysis will appear in this month's issue of 'The Astronomer', Guy M Hurst