SIMBAD references

Vitali Nevski, Vitebsk, Belarus, reports the discovery of a possible supernova (mag approximately 17.7) on ten unfiltered 180-s CCD images (limiting mag 20.0) taken on Apr. 10.88 UT with a 0.3-m reflector + CCD. The new object, which appeared at mag approximately 17.5 on Apr. 11.81, is located at R.A. = 12:03:10.95, Decl. +44:31:43.1 (equinox 2000.0), which is about 19".5 east and 10" south of the center of the galaxy NGC 4051. Nothing is visible at this position on a Palomar Sky Survey red plate obtained on 1996 Mar. 17 or a blue plate obtained on 1990 Jan. 29 (via the Digitized Sky Survey; limiting mag 21.5). The discovery images are posted at the following website URLs: http://tinyurl.com/y2f8mwv and http://tinyurl.com/y5h3rfb. Following posting on the Central Bureau's unconfirmed-objects webpage, A. Maksym (Terskol, Russia) writes that he imaged 2010br with a 0.6-m reflector on Apr. 11.819, yielding magnitude R = 17.9 and position end figures 10s.90, 43".3 (UCAC2 catalogue). Maksym has posted his image at URL http://tinyurl.com/y83bq2s. Also, L. Elenin (Lyubertsy, Russia) and M. Schwartz (Rio Rico, Arizona, USA) report that 2010br appears at mag R = 17.1 and V = 17.7 on a CCD image obtained on Apr. 13.435 by Schwartz with a 0.81-m telescope at the Tenagra II Observatory and measured by Elenin, who provides position end figures 10s.93, 43".6; 2010btr is not visible on Digitized Sky Survey images (no dates, bandpasses, or limiting magnitudes provided).