Electronic Telegram No. 2115
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)
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SUPERNOVA 2010B IN NGC 5370
     S. Nakano, Sumoto, Japan, reports the discovery by Masaki Tsuboi
(Asakita-ku, Hiroshima) of an apparent supernova (mag 14.4) on 30-s,
unfiltered CCD frames (limiting mag 17.7) taken around Jan. 7.730 UT using a
0.30-m f/5.3 reflector + unfiltered CCD.  The new object, designated 2010B,
was measured by Tsuboi to be located at R.A. = 13h54m08s.7, Decl. =
+60d40'50".4 (equinox 2000.0), which is 5".1 west and 9".1 north of the
center of NGC 5370; Nakano measures position end figures 08s.82, 49".6 and
magnitude 14.1 from the discovery image (and 09s.49, 40".7 for the center of
the galaxy).  Nothing is visible at this location on Tsuboi's past frames
taken on 2009 Sept. 6 and Nov. 21 UT (limiting mag 16.7) and on the Digitized
Sky Survey (DSS), and he reports mag 14.5 for 2010B on Jan. 8.661.  Nakano
adds that K. Kadota (Ageo, Saitama-ken, Japan) has measured position end
figures 08s.74, 50".4 and mag 14.4 from an unfiltered CCD frame (limiting
magnitude 19.0) taken by K. Itagaki (Teppo-cho, Yamagata, Japan) on Jan. 8.64
using a 0.30-m f/7.8 reflector at the Takanezawa Station, Tochigi-ken, noting
that nothing is visible at this position on red and infrared DSS images from
1997.  Kadota also co-added ten 60-s unfiltered CCD frames (limiting mag
18.9) on Jan. 8.757 with a 0.25-m f/5 reflector, yielding mag 14.5 and
position end figures 08s.77, 50".2.
     Following posting on the Central Bureau's unconfirmed-objects webpage,
Veli-Pekka Hentunen (Varkaus, Finland) writes that he obtained four 150-s
unfiltered CCD images (limiting mag 17.7) with a Celestron C14 XLT telescope
(+ Optec NextGen 0.5x focal reducer + SBIG ST 8 XME camera) on Jan. 8.72,
yielding mag 14.4 and position end figures 08s.81, 50".5; nothing is visible
at this position on a Palomar Sky Survey F plate (limiting red magnitude 20.8).


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 January 8                   (CBET 2115)              Daniel W. E. Green