Electronic Telegram No. 1645 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 2009A [Editor's note: this text replaces that on CBET 1643; the designation 2008ir will be re-used if necessary.] G. Pignata, J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, P. Lopez, S. Silva, G. Folatelli, D. Iturra, R. Cartier, and F. Forster, Universidad de Chile; B. Conuel, Wesleyan University; and D. Reichart, K. Ivarsen, A. Crain, D. Foster, M. Nysewander, and A. LaCluyze, University of North Carolina at Chapel Hill, on behalf of the CHASE project, report the discovery of an apparent supernova (mag approximately 16.0 +/- 0.2) on unfiltered images taken on Jan. 2.11 and 3.21 UT with the 0.41-m 'PROMPT 3' telescope located at Cerro Tololo. The new object is located at R.A. = 1h52m44s.34 +/- 0".1, Decl. = -3o23'48".2 +/- 0".1 (equinox 2000), which is about 6".4 west and 7".3 north of the center of the apparent host galaxy. Nothing is visible at this position on archival images taken on 2007 Dec. 9.16 and 13.10 (limiting mag 18.0). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 January 3 (CBET 1645) Daniel W. E. Green