Electronic Telegram No. 640 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://cfa-www.harvard.edu/iau/cbat.html SUPERNOVA 2006gs IN NGC 3977 S. Nakano, Sumoto, Japan, reports the discovery by K. Itagaki (Teppo-cho, Yamagata, Japan) of an apparent supernova (mag 17.0) on unfiltered CCD frames taken around Sept. 22.80 and 23.40 UT using a 0.60-m f/5.7 reflector (limiting magnitude 19.5). The new object is located at R.A. = 11h56m08s.50 +/- 0s.02, Decl. = +55o23'29".8 +/- 0".4 (equinox 2000.0), which is 11" east and 3" north of the center of NGC 3977. Nothing is present at this location on Digitized Sky Survey images. Limiting magnitudes for 2006gs from Itagaki's search frames: 2005 May 15, [19.0; 2006 Sept. 21, [17.5. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 September 23 (CBET 640) Daniel W. E. Green