Electronic Telegram No. 1418 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 2008dn IN UGC 11946 S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, reports that a spectrum (range 350-740 nm) of 2008dn (cf. CBET 1413), obtained on June 28.47 UT by M. Calkins with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-II-plateau supernova around one month past explosion. Cross- correlation with a library of supernova spectra using the "Supernova Identification" code (Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2008dn is most similar to the type-II-plateau supernova 1999gi at one month past explosion. Adopting a recession velocity of 5472 km/s for the host galaxy (from The Updated Zwicky Catalog), the maximum absorption in the H_alpha line (rest 656.3 nm) is blueshifted by roughly 7000 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2008 CBAT 2008 June 29 (CBET 1418) Daniel W. E. Green