Electronic Telegram No. 2304 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 2010dr IN MCG +08-1-3 T. Boles, Coddenham, England, reports the discovery of an apparent supernova (mag 18.5) on unfiltered CCD images taken on June 3.086 and 4.057 UT with a 0.35-m reflector. The new object is located at R.A. = 23h52m13s.04 +/- 0s.01, Decl. = +47o23'42".5 +/- 0".1 (equinox 2000.0), which is approximately 16".4 east and 1".1 south of the center of MCG +08-1-3. Nothing is present at this position on Boles' images from 2009 Oct. 18 and Sept. 10 (limiting mag 19.5) or on Digitized Sky Survey plates from 1989 Sept. 28 (limiting red mag 20.5) and 1993 Aug. 21 (limiting blue mag 21.0). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 June 4 (CBET 2304) Daniel W. E. Green