Electronic Telegram No. 335 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://cfa-www.harvard.edu/iau/cbat.html SUPERNOVA 2005mf IN UGC 4798 F.-Y. Bian, Y.-Q. Lou, X.-F. Wang, and Y. Yang, Tsinghua Center for Astrophysics (THCA), Tsinghua University, Beijing; and Y.-L. Qiu, National Astronomical Observatories of China (NAOC), report the discovery of an apparent supernova (mag about 17.4) on unfiltered CCD images taken on Dec. 25.67 UT with the 0.8-m THCA-NAOC Telescope (TNT) in the course of the THCA Supernova Survey. The new object is located at R.A. = 9h08m42s.33, Decl. = +44o48'51".4 (equinox 2000.0), which is 5".9 west and 13".3 north of the center of the galaxy UGC 4798. Nothing was visible at this location of the new object on TNT template images obtained on Oct. 31, Nov. 13, 25 (limiting mag 18.5), and Dec. 13. SN 2005mf was confirmed at mag about 17.3 on an image taken on Dec. 26.58. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2005 CBAT 2005 December 27 (CBET 335) Daniel W. E. Green