Electronic Telegram No. 1722 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 2009at IN NGC 5301 A. Harutyunyan, Telescopio Nazionale Galileo (TNG); and F. Bufano and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, report that a spectrogram (range 350-780 nm, resolution 1.4 nm) of 2009at (cf. CBET 1718), obtained on Mar. 14.00 UT with the TNG (+ DOLORES), shows it to be a young type-II supernova. Assuming a recession velocity of 1503 km/s (Sloan Digital Sky Survey data release 4, 2005; via NED) for the host galaxy, the "GELATO" spectrum-comparison code (Harutyunyan et al. 2008, A.Ap. 488, 383; available at https://gelato.tng.iac.es) provides good fits to spectra of type-II supernovae near explosion. One of the fits, with SN 2008aw at ten days after discovery, can be seen at the following website URL: https://gelato.tng.iac.es/plots/plot_TiEepj0QK72n.png. The expansion velocity deduced from the H-alpha absorption is about 11700 km/s. Further to CBET 1718, S. Nakano clarifies that he simply averaged ten measurements that were made by Ikari. Corrigendum: on line 10, FOR Nov. 11.760, READ Mar. 11.760, E. Prosperi, Larciano, Italy, reports that 2009at was at unfiltered CCD mag 15.5 on Mar. 12.919 UT (0.35-m f/10 Schmidt-Cassegrain reflector). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 March 15 (CBET 1722) Daniel W. E. Green