Electronic Telegram No. 2116 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 2009mu IN ESO 374-3 M. Stritzinger, Las Campanas Observatory; G. Folatelli, Universidad de Chile; and G. Pignata, Universidad Andres Bello, on behalf of the Millennium Center for Supernova Science, report that they obtained an optical spectrum of 2009mu (cf. CBET 2091) on Jan. 6.1 UT with the Gemini (+ GMOS) telescope. The spectrum reveals that 2009mu is a type-IIb supernova around a hundred days or more past maximum. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 January 8 (CBET 2116) Daniel W. E. Green