F. Yuan, University of Michigan; R. Quimby, California Institute of Technology (CIT); E. Rykoff, University of California at Santa Barbara; M. D. Sisson, D. Chamarro, C. Akerlof, T. McKay, and J. M. Miller, University of Michigan; and J. C. Wheeler, University of Texas – on behalf of the ROTSE collaboration – and J. S. Bloom, R. J. Foley, M. Modjaz, and A. A. Miller, University of California at Berkeley (UCB); and P. J. Brown, Pennsylvania State University, report the discovery of a type-IIn supernova in unfiltered CCD images taken with the 0.45-m ROTSE-IIIb telescope at McDonald Observatory: SN 2008 UT R.A. (2000.0) Decl. Mag. Offset 2008am Jan. 10.41 12 28 36.25 +15 34 49.1 18.7 1``.0 W, 0’'.6 S SN 2008am reached mag 18.2 +/- 0.2 on Jan. 15.36 UT and then decayed; the most recent detection showed it at mag 18.6 +/- 0.1 on Feb. 12.27 (the magnitudes given above are unfiltered but calibrated to the SDSS r band). A finding chart of 2008am can be found at the following website URL: http://www.rotse.net/rsvp/j122836.3+153449/j122836.3+153449.jpg.
