Electronic Telegram No. 2155
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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COMET 17P/HOLMES
     Z. Sekanina, Jet Propulsion Laboratory, calls attention to the need
for monitoring this comet's integrated brightness as a measure of activity
between now and the next return to the sun in 2014.  Sudden, unpredictable
flare-ups are not ruled out following the enormous explosion in October 2007.
At present, the comet is favorably placed for observation until June 2010, and
then again from December 2010 to July 2011, from January to August 2012, and
from February to October 2013.  Except for a few months around conjunctions
with the sun, the comet should be observable throughout the orbit and never
fainter than visual magnitude 24.5.  Currently, its brightness is expected to
be between 19 and 23.5.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2010 CBAT
2010 January 29                  (CBET 2155)              Daniel W. E. Green