Electronic Telegram No. 2448 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 APPARENT NOVA IN M31: M31N 2010-09a Syuichi Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki (Teppo-cho, Yamagata) of an apparent nova (mag 17.2) in M31 on unfiltered CCD frames (limiting magnitude 20.5) taken on Sept. 4.552 UT using a 0.60-m f/5.7 reflector (+ Bitran BT-214E camera). The new object is located at R.A. = 0h42m23s.32 +/- 0s.03, Decl. = +42o17'08".6 +/- 0".3 (equinox 2000.0). Additional magnitudes for M31N 2010-09a measured by Itagaki: 1986 Nov. 27, [21.0 (Digitized Sky Survey red plate); 2007 Oct. 13, 20.0; 2010 Aug. 21.631, [19.0; Sept. 1.666, 17.8 (pre-discovery); 5.490, 18.1 (limiting mag 20.5). The discovery image is visible at http://www.k-itagaki.jp/images/pn-m-31.jpg. Nakano also forwards a confirming report by T. Yusa (Osaki) on Sept. 5.500, in which an unfiltered CCD image taken with a 0.30-m f/9.9 Cassegrain telescope (+ BSTL-1001E camera) shows M31N 2010-09a at mag 17.5 and with position end figures 23s.29, 08".9. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 September 6 (CBET 2448) Daniel W. E. Green