2010CBET.2299....1N

S. Nakano, Sumoto, Japan, reports the discovery by Koichi Itagaki (Teppo-cho, Yamagata) of an apparent supernova (mag 17.5) on unfiltered CCD frames (limiting mag 19.0) taken on May 31.523 UT using a 0.60-m f/5.7 reflector (+ Bitran BT-214E camera). The new object is located at R.A. = 10:18:19.89, Decl. = +41:26:28.8 (equinox 2000.0), which is 33" east and 61" north of the center of NGC 3184. Nothing is visible at this position on Itagaki's past images taken on 2009 Mar. 30.612 (limiting mag 19.0) and on 2010 May 21.503 (limiting mag 18.0) or on the Digitized Sky Survey. Itagaki's discovery image has been posted at the following website URL: http://www.k-itagaki.jp/images/psn3184.jpg. After posting on the Central Bureau's unconfirmed-objects webpage, T. Yusa (Osaki, Japan) writes that fourteen co-added 60-s unfiltered CCD exposures (limiting mag 19.5) taken on June 1.48 with a 0.30-m f/8.2 reflector (+ SBIG ST-6 camera) yield mag 17.1 and position end figures 19s.84, 28".4 for 2010dn.