Electronic Telegram No. 2443 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2010hh IN NGC 6524 S. Nakano, Sumoto, Japan, reports that K. Kadota (Ageo, Japan) obtained a co-added image (limiting mag 18.6) of 2010hh (cf. CBETs 2435, 2440) from twelve 120-s unfiltered CCD frames taken around Sept. 3.675 UT with a 0.25-m f/5 reflector (+ SBIG ST-9E camera), yielding mag 17.7 and position R.A. = 17h59m18s.39, Decl. = +45d52'32".1 (equinox 2000.0). J. M. Silverman, J. Choi, A. V. Filippenko, and F. J. D. Serduke, University of California, Berkeley, report that inspection of a CCD spectrum (range 340-970 nm), obtained on SepT. 3 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2010hh is a type-Ia supernova near maximum brightness. After removal of the host-galaxy recession velocity of 5698 km/s (Falco et al. 1999, PASP 111, 438), the absorption minimum of the Si II 635.5-nm line is found to be blueshifted by about 12600 km/s. The Si II line at 597 nm is quite strong, as is Ti II absorption around 420-430 nm, suggesting that 2010hh is subluminous like SN 1991bg (e.g. Filippenko et al. 1992, AJ 104, 1543), though perhaps not quite as extreme. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 September 4 (CBET 2443) Daniel W. E. Green