Electronic Telegram No. 2314 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbat@iau.org; cbatiau@eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2010dx IN NGC 7038 G. Pignata and M. Cifuentes, Universidad Andres Bello; J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, S. Silva, G. Folatelli, R. Cartier, F. Forster, and S. Marchi, Universidad de Chile; B. Conuel, Wesleyan University; and D. Reichart, K. Ivarsen, J. Haislip, 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 17.4 +/- 0.3) on an unfiltered image taken on June 8.17 UT with the 0.41-m 'PROMPT 1' telescope located at Cerro Tololo. The new object is located at R.A. = 21h15m11s.09 +/- 0".1, Decl. = -47o13'34".3 +/- 0".1 (equinox 2000.0), which is about 36".4 east 20".2 south of the center of the galaxy NGC 7038. Nothing is visible at this position on archival images taken on May 10.34 and Apr. 28.30 (limiting mag 18.5). SN 2010dx is also present in images taken on June 9.19 (at mag approximately 17.1) and June 1.28 (at mag approximately 17.0). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 June 9 (CBET 2314) Daniel W. E. Green