Electronic Telegram No. 2486 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network POSSIBLE SUPERNOVA IN NGC 5430 Guoyou Sun, Wenzhou, Zhejiang, China; and Xing Gao, Urumqi, Xinjiang, China, report the discovery of a possible supernova (mag approximately 17.2) on 60-s survey images (limiting mag about 19) taken by Xing Gao in the course of the Xingming Observation Sky Survey at Mt. Nanshan around Oct. 3.605 UT using an unfiltered CCD camera with a Celestron C14 Schmidt-Cassegrain telescope. The new object is located at R.A. = 14h00m47s.12 +/- 0s.12, Decl. = +59d20'17".0 +/- 0".2 (equinox 2000.0; measured by Sun), which is 13".7 west and 33".5 north of the nucleus of NGC 5430. Nothing is visible at this position on a Digitized Sky Survey image from 1997 Apr. 8 (limiting mag about 19.5; no bandpass stated). Additional magnitudes for the variable provided by Sun: Oct. 4.578, 17.2; 5.588, 16.9; 6.584, 16.7. Following posting on the Central Bureau's unconfirmed-objects webpage, G. Cortini (Predappio, Italy, 0.35-m telescope) reports that the variable appeared at mag 17.3 with position end figures 47s.08, 17.0 (offset 1".3 east, 34" north of the center of NGC 5430) on several unfiltered CCD images (limiting mag about 18.5) taken on Oct. 6.81. S. Nakano, Sumoto, Japan, forwards mag 17.0 and position end figures 47s.09, 16".6 (offset 10" east, 33" north) from unfiltered CCD images (limiting mag 18.0) taken by K. Kadota (Ageo, Japan, 0.25-m f/5 reflector + SBIG ST-9E camera) on Oct. 6.080. T. Yusa, Osaki, Japan, reports mag 17.0 and position end figures 47s.10, 16".7 (offset 10" east, 33" north of the center of NGC 5430) from unfiltered CCD frames (limiting mag 18.5) taken on Oct. 7.402 with a 0.30-m f/7 Cassegrain telescope (+ SBIG STL-1001E camera). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 October 8 (CBET 2486) Daniel W. E. Green