Electronic Telegram No. 2516 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 APPARENT NOVA IN M31: M31N 2010-10d An apparent nova in the galaxy M31 has been discovered by several different observers. Koichi Nishiyama, Kurume, Japan; and Fujio Kabashima, Miyaki, Japan, report the discovery of a possible nova of mag 17.8 on ten 40-s unfiltered CCD frames (limiting magnitude 19.5) taken around Oct. 29.478 UT with a Meade 200R 0.40-m f/9.8 reflector (+ SBIG STL1001E camera). The new object is located at R.A. = 0h42m36s.91, Decl. = +41o19'29".9 (equinox 2000.0), which is 84" west and 201" north of the center of the galaxy M31. Nothing is visible at this position on their past frames taken on Oct. 26.550 and 27.642 (limiting magnitude 19.3 ) or on a Digitized Sky Survey image from 1986 Nov. 27 (limiting red mag 18.7). The nearest star in the Massey M31 catalogue (cf. website URL http://www.lowell.edu/users/massey/lgsurvey.html) has position end figures 37s.01, 30".8 (distance 1".4; magnitudes V = 22.6, B = 23.4, R = 22.5). Guoyou Sun, Wenzhou, Zhejiang, China; and Xing Gao, Urumqi, Xinjiang, China, report the discovery of a possible nova at mag approximately 18.5 on several 60-s unfiltered survey images (limiting mag about 19.5) taken by Xing Gao in the course of the Xingming Observatory Sky Survey around Oct. 29.587 UT using a Celestron C14 Schmidt-Cassegrain telescope at Mt. Nanshan. The new object is approximately located at R.A. = 0h42m36s.97, Decl. = +41o19'28".7 (equinox 2000.0), which is about 110" west and 200" north of the center of NGC 224 = M31. Nothing is visible at this position on archival images taken on Oct. 26.536 (limiting mag 19.0), Oct. 27.602 (limiting mag 19.5), or Oct. 28.661 (limiting mag 19.5). The images can be seen at the following website URL: http://www.xjltp.com/XOSS/XM10AK/XM10AK.htm. Kamil Hornoch, Astronomical Institute, Ondrejov, reports his discovery of an apparent nova in M31 on a co-added 1260-s R-band CCD frame taken on Oct. 29.729 UT with the 0.65-m telescope at Ondrejov. The new object is well visible on the co-added frame, as well as on single images used for the co-added frame, but is not present on numerous archive images taken at Lelekovice and Ondrejov. The object is visible also on a pre-discovery Ondrejov R-band CCD frame taken on Oct. 28.719 UT. Available R-band magnitudes for M31N 2010-10d, measured by Hornoch: Oct. 22.934 UT, [20.6 (K. Hornoch and P. Hornochova, 0.65-m telescope at Ondrejov); 28.719, 19.8 +/- 0.25 (Hornoch and M. Wolf, 0.65-m telescope at Ondrejov); 29.729, 17.85 +/- 0.1 (Hornoch, 0.65-m telescope at Ondrejov). M31N 2010-10d is located at R.A. = 0h42m36s.91, Decl. = +41o19'29".6 (equinox 2000.0), which is 84" west and 201" north of the center of M31. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 October 30 (CBET 2516) Michael Rudenko