Electronic Telegram No. 1302 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 2008ax IN NGC 4490 W. Li and A. V. Filippenko, University of California, Berkeley, write that follow-up observations of SN 2008ax show that, after an initial decline in the B band between Mar. 4 and 5 UT, the supernova has been steadily brightening since discovery, with B = 15.3, V = 14.6, and R = 14.1 on Mar. 12.48. This is approximately 2 mag brighter than at discovery (cf. CBET 1280). The brightening rate of 2008ax is about three times that of the type-IIb supernova 1993J. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2008 CBAT 2008 March 14 (CBET 1302) Daniel W. E. Green