------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 1514 2000 Apr 15 06.17UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK GMH at AST.STAR.RL.AC.UK WORLD WIDE WEB http://www.demon.co.uk/astronomer ------------------------------------------------------------------- SUPERNOVA 2000bk IN NGC 4520 On April 11/12 Mark Armstrong imaged a suspect in NGC 4520 (nuclear position: RA 12 33 49, Dec -07 22 30 (2000)). He estimated it to be of magnitude 17, 60 arcsec east and 5 arcsec south of the nucleus. Over the following three hours no movement was detected. There was no trace of the suspect on his master of 2000 Jan 10 and a subsequent patrol from March 4/5. A check of the MPC database down to magnitude 20 was negative and POSS I and POSS II red showed no trace of the object. The following announcement appeared in IAUC 7402: "Mark Armstrong, Rolvenden, Kent, England, reports his discovery of an apparent supernova (mag 17) visible on four CCD images taken between Apr. 11.942 and 12.090 UT. SN 2000bk is located at R.A. 12h33m53s.94, Decl. -7 22'42".9 (equinox 2000.0; mean of measurements from four frames), which is 61" east and 10" south of the nucleus of NGC 4520. Earlier images taken by Armstrong on Jan. 10 and Mar. 4-5 show nothing at this position (limiting mag 18), neither is anything visible on the IIIa-J SERC J survey image taken on 1983 Apr. 15 (limiting mag 23) or on the IIIa-F Palomar Sky Survey plate taken on 1993 Feb. 23 (limiting mag 22). W. Li, University of California at Berkeley, reports that a prediscovery image of SN 2000bk was obtained with the 0.8-m Katzman Automatic Imaging Telescope on Apr. 7.3 UT, showing the new object at mag about 17.0." Our congratulations go to Mark on this further discovery. NGC 4520 is in Virgo and it is well placed for evening observation at the moment. At magnitude 17 it should be within the range of most CCD equipped observers. Nick James (ndj@astro1.demon.co.uk).