Electronic Telegram No. 166 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 2005ch Further to IAUC 8537, E. S. Rykoff reports the discovery of an apparent supernova in unfiltered CCD images taken on June 8.83 (at mag about 15.8) and 9.56 UT (mag about 15.5) with the 0.45-m ROTSE- IIIc telescope at the HESS site in Namibia and the ROTSE-IIIa telescope at Siding Spring Observatory. SN 2005ch is located at R.A. = 14h22m06s.77, Decl. = +1o59'35".7 (equinox 2000.0), which is 0".9 north and 3".1 east of the core of the apparent host galaxy (whose SDSS magnitude is given as g' = 20.0). Nothing is visible at this location on ROTSE-IIIc images taken on May 27.86 (limiting mag about 17.5). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the formal IAU Circulars. (C) Copyright 2005 CBAT 2005 June 9 (CBET 166) Daniel W. E. Green