Electronic Telegram No. 2310 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbat@iau.org; cbatiau@eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2010dw Jure Skvarc reports the discovery of an apparent supernova on four clear-filtered CCD images taken on June 5.94-5.99 UT with the 60-cm f/3.3 Cichocki reflector in the course of the Comet and Asteroid Search Program (PIKA) at the Crni Vrh Observatory. The new object, which appears at magnitude R = 17.3 on a confirming image taken by B. Mikuz on June 6.89 with the same telescope, is located at R.A. = 15h22m40s.31, Decl. = -5o55'15".9 (equinox 2000.0), which is 4".5 east and 5".5 north of the galaxy designated 2MASX J15224062-0555214. Nothing is visible at this position on archival PIKA images obtained on 2006 Apr. 4.12 (limiting mag 18.0) or on a Palomar Sky Survey image from 1955 May 20. A CCD image taken by S. Maticic with the same Crni Vrh telescope on June 7.89 yields R = 17.1 for 2010dw, as measured by Skvarc. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 June 8 (CBET 2310) Daniel W. E. Green