SUPERNOVA 2010gi IN IC 4660
S. Nakano, Sumoto, Japan, reports the discovery by Masaki Tsuboi (Kuchita-minami, Asakita-ku, Hiroshima) of an apparent supernova (mag 15.3) on unfiltered CCD frames (limiting mag 18.2) taken on July 18.514 UT using a 0.30-m f/5.3 reflector (+ ST-2000XM camera); the new object was measured by Tsuboi to be located at R.A. = 17h21m46s.1, Decl. = +75d50'45".4 (equinox 2000.0), which is 3".2 east and 10".6 south of the center of IC 4660.
Nothing is visible at this position on Tsuboi's past frames taken on May 13 and 30 UT or on a red Digitized Sky Survey photograph. Nakano measures mag
14.9 and position end figures 46s.0, 44".3 (offset 1".8 east, 6".4 south of the center of IC 4660) from an image (limiting magnitude 17.8 ) taken by Tsuboi on July 18.658.
After posting on the Central Bureau's unconfirmed-objects webpage, Toru Yusa (Osaki, Japan) reports that he confirmed 2010gi at mag 15.0 on two 120-s unfiltered CCD exposures (limiting mag 18.0) taken on July 19.153 UT remotely using a 0.25-m f/3.4 reflector (+ SBIG ST-10XME camera) at the RAS Observatory near Mayhill, NM, U.S.A., yielding position end figures 46s.06, 44".5 (USNO-B1.0 catalogue) and offset 2".9 east, 9".8 south; he has posted his image at
http://space.geocities.jp/yusastar/PSNinIC4660_100719.htm.Also, D. D. Balam, Dominion Astrophysical Observatory, writes that imaging using the 1.82-m Plaskett telescope of the National Research Council of Canada shows the new source to be at magnitude R = 15.8 on July 19.23 with offset 3".7 east, 9".4 south of the core of IC 4660.
NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
superseded by text appearing later in the printed IAU Circulars.
(C) Copyright 2010 CBAT
2010 July 19 (CBET 2376) Daniel W. E. Green
