Electronic Telegram No. 548 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://cfa-www.harvard.edu/iau/cbat.html SUPERNOVA 2006db Further to IAUC 8622, R. Quimby and P. Mondol, University of Texas, report the discovery of an apparent supernova in unfiltered CCD images taken on June 16.18 (at mag about 17.2) and 17.17 UT (mag about 16.8) using the 0.45-m ROTSE-IIIb telescope at the McDonald Observatory. SN 2006db is located at R.A. = 11h55m38s.69, Decl. = +44o23'01".4 (equinox 2000.0), which is 4".6 east and 0".5 north of the center of the apparent host galaxy (with a catalogued redshift of z = 0.023 from the Sloan Digital Sky Survey). SN 2006db was found by subtracting a co-addition of images taken between 2005 Mar. 4 and 2005 Apr. 8 (limiting mag about 18.4) from the 2006 June images. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 June 17 (CBET 548) Daniel W. E. Green