Electronic Telegram No. 1089 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2007kh F. Yuan, J. Aretakis, and C. Akerlof, University of Michigan; R. Quimby, California Institute of Technology; and J. C. Wheeler, University of Texas, on behalf of the ROTSE collaboration, report the discovery of a supernova (mag 18.9 +/- 0.1; calibrated relative to USNO-B1.0 red magnitudes) on unfiltered CCD images taken with the 0.45-m ROTSE-IIIb telescope at McDonald Observatory on Sept. 7.45 UT; 2007kh reached mag 18.1 +/- 0.1 on Sept. 14.33 and remained near mag 18 for about nine days (last observed at mag 18.3 +/- 0.2 on Sept. 25.24). The new object is located at R.A. = 3h15m12s.10, Decl. = +43o10'13".0 (equinox 2000.0; uncertainty < 1"). Nothing is visible (including a possible host galaxy) at this position in the Digitized Sky Survey image or on any USNO archive plates. A finding chart of 2007kh can be found at the following website URL: http://www.rotse.net/transients/j0315+4310/070919_031512+431013.jpg. Quimby adds that a spectrum (420-890 nm) of 2007kh, obtained on Sept. 25.29 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by J. Caldwell, E. Terrazas, and V. Riley, shows it to be a type-Ia supernova. The spectrum is similar to that of SN 1994D at about 3 days after maximum light (Patat et al. 1996, MNRAS 278, 111). Using the spectrum of SN 1994D as a template, the redshift is found to be approximately z = 0.05. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 September 26 (CBET 1089) Daniel W. E. Green