Electronic Telegram No. 1712 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 2009ap IN ESO 138-27 G. Pignata, J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, P. Lopez, S. Silva, G. Folatelli, D. Iturra, R. Cartier, F. Forster, and S. Marchi, 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 16.9 +/- 0.2) on an unfiltered image taken on Mar. 5.38 UT with the 0.41-m 'PROMPT 5' telescope located at Cerro Tololo. The new object, which is also present in an image taken on Feb. 24.29 at mag approximately 17.2 +/- 0.3, is located at R.A. = 17h26m43s.23 +/- 0".1, Decl. = -59o55'57".9 +/- 0".1 (equinox 2000), which is about 2".9 west and 0".1 south of the center of the galaxy ESO 138-27. Nothing is visible at this position on archival images taken on 2008 Aug. 9.03 (limiting mag 18.5) and Sept. 11.14 (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 NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars.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 March 5 (CBET 1712) Daniel W. E. Green