Electronic Telegram No. 973 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2007cm IN NGC 4644 W. Kloehr, Schweinfurt, Germany, reports the discovery of an apparent supernova (mag about 16.1) on six unfiltered CCD images taken on May 24.024 UT with a 20-cm Meade DSI-Pro II Schmidt-Cassegrain telescope. The new object is located at R.A. = 12h42m45s.18, Decl. = +55o08'57".1 (equinox 2000.0), which is 21".5 east and 13".5 north of the center of NGC 4644. A Palomar Sky Survey II image shows nothing at this position. Kloehr provides the following additional unfiltered CCD magnitudes for 2007cm: Mar. 27, [17.5 (Kloehr); May 16.22, [19.0 (W. Li, University of California at Berkeley, KAIT); 24.21, 17.5 (Li); 24.398, 16.0 (M. Nicholson, Mayhill, NM); 24.854, 16.2 (A. Dimai and M. Migliardi, Cortina d'Ampezzo, Italy). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 May 25 (CBET 973) Daniel W. E. Green