Electronic Telegram No. 2599 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2010kx IN NGC 7645 S. Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki (Teppo-cho, Yamagata) of an apparent supernova (mag 17.5) on unfiltered CCD frames (limiting magnitude 18.5) taken on Dec. 19.383 (0.50-m f/6 reflector) and 20.360 UT (0.60-m f/5.7 reflector). The new object is located at R.A. = 23h23m46s.37, Decl. = -29d23'10".0 (equinox 2000.0), which is 11".1 west and 3".3 north of the center of NGC 7645. Nothing is visible at this position on his many past frames, including one taken on 2009 Oct. 19.51 (limiting mag 19.0) and another on 2010 Dec. 8.41 (limiting mag 18.0) or on the Digitized Sky Survey. Itagaki has posted his images at the following website URL: http://www.k-itagaki.jp/images/psn-7645.jpg. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 December 21 (CBET 2599) Daniel W. E. Green