Electronic Telegram No. 1793 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 2009W A. U. Sugden and J. J. Salzer, Indiana University, report that images of 2009W (cf. CBETs 1683, 1689) were obtained in a series of exposures taken with the WIYN 0.9-m telescope on Kitt Peak using R-band and narrow-band H_alpha filters on Mar. 19.48 UT; the supernova's magnitude was measured to be R = 18.8, and its position was measured to be R.A. = 16h23m45s.68, Decl. = +11o44'08".9 (equinox 2000.0). No source is visible at the location of 2009W in Sloan Digital Sky Survey images of the field (limiting r' magnitude about 23). SN 2009W was detected as an H_alpha source in their WIYN data, with an equivalent width of about 18 nm. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 May 5 (CBET 1793) Daniel W. E. Green