2010CBET.2342....1H

Kamil Hornoch, Ondrejov Observatory, reports the discovery by P. Hornochova and himself of another apparent nova in M31 from a co-added 1620-s R-band CCD frame taken with the 0.65-m telescope at Ondrejov on June 28.014 UT. The new object is located at R.A. = 0:44:22.46, Decl. = +41:28:14.5 (equinox 2000.0), which is 1105" east and 726" north of the center of the galaxy M31. M31N 2010-06b is visible on single images used for the co-added image, as well as on a pre-discovery co-added 630-s R-band image taken by Hornoch on June 26.997 with the same instrumentation, but the presumed nova is not present on available archive images. Also, the object is not present down to magnitude R = 23 on a deep R-band image obtained in the course of data collecting for the Local Group Survey M31 catalogue (Massey et al. 2006, A.J. 131, 2478). Available R-band magnitudes for M31N 2010-06b: 2006 Jan. 6.084 UT, [21.4 (J. Gallagher and P. Garnavich, 0.91-m telescope at Kitt Peak); 25.086, [21.6 (Gallagher and Garnavich); 2010 June 26.997, 19.0 ± 0.3 (K. Hornoch, 0.65-m telescope at Ondrejov); 28.014, 19.1 ± 0.15 (Hornoch and P. Hornochova, 0.65-m telescope at Ondrejov).