Electronic Telegram No. 2176 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Room 209; Dept. of Earth and Planetary Sciences; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbat@cfa.harvard.edu; dwe_green@eps.harvard.edu URL http://www.cfa.harvard.edu/iau/cbat.html PROBABLE NOVA IN OPHIUCHUS S. Nakano, Sumoto, Japan, reports the discovery by Hideo Nishimura (Miyawaki, Kakegawa, Shizuoka-ken, Japan) of a 9th-magnitude possible nova on two 13-s frames taken on Feb. 18.845 UT using a Minolta 120-mm f/3.5 lens and a Canon EOS 5D Digital camera mounted on a Takahashi EM100 equatorial telescope. Nakano measured limiting mag 12.7 from Nishimura's JPEG image, mag 9.4 for the variable, and the following precise position (uncertainty +/- 4"): R.A. = 17h26m32s.19, Decl. = -28d49'36".3 (equinox 2000.0). Nishimura notes that nothing is visible at this position on his frames taken during each month in the span 2009 Feb.-Oct. 15 and on 2010 Feb. 2, 4, 5, 7, and 13.84 UT (limiting mag 11). Nakano forwards the following position end figures for the presumed nova from an unfiltered CCD exposure taken by K. Itagaki on Feb. 19.778 using a 0.30-m f/7.8 reflector (+ Bitran BT-214E CCD camera) at the Takanezawa station, Tochigi-ken, Japan: 32s.08, 38".5 (magnitude 9.0); his image is posted at the following website URL: http://www.k-itagaki.jp/images/pn-oph.jpg. Nakano further notes that K. Kadota (Ageo, Japan, 0.25-m f/5 reflector + SBIG ST-9E CCD camera) measured mag 8.9 and position end figures 32s.11, 39".0 from four 4-s exposures (limiting mag 16.5) taken on Feb. 19.825. After posting on the Central Bureau's unconfirmed-objects webpage, R. Kaufman (Bright, Victoria, Australia) writes that a green-channel unfiltered DSLR image taken with a Canon 400D camera on Feb. 15.651 and 15.656 shows the probable nova at mag approximately mag 9.4 (close to the V band). An image by Kaufman taken with a 55-mm f/4 camera lens (three stacked 30-s frames) is visible via the following website URL: http://tinyurl.com/yfol3nu. S. Kiyota (Tsukuba, Japan) reports that an image taken remotely on Feb. 19.48 with a 30-cm reflector (+ FLI IMG1024 CCD camera) near Mayhill, NM, U.S.A., yields position end figures 32s.11, 38".5 and the following magnitudes for the new object: B = 10.36, V = 9.53, R_c = 9.02, I_c = 8.40. Kiyota adds that nothing is visible at this position on Digitized Sky Survey plates. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 February 19 (CBET 2176) Daniel W. E. Green