Electronic Telegram No. 644 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 2006gy IN NGC 1260 Further to IAUC 8622 and 8736, R. Quimby, University of Texas, reports the discovery of an apparent supernova in unfiltered CCD images taken with the 0.45-m ROTSE-IIIb telescope at the McDonald Observatory. SN 2006gy is located at R.A. = 3h17m27s.06, Decl. = +41d24'19".5 (equinox 2000.0), which is 2".0 west and 0".4 north of the center of NGC 1260 (z = 0.019, from Bernardi et al. 2002, A.J. 123, 2990, via NED). Available approximate magnitudes for 2006gy: Sept. 18.30 UT, 15.0; 23.28, 14.8; 24.29, 14.9. The new object was found by subtracting a co-addition of images taken between 2005 Sept. 28 and Oct. 25 (limiting mag about 18.1) from the 2006 September images. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 September 24 (CBET 644) Daniel W. E. Green