[BAA 00310] Comet 2007 F1 (LONEOS)

[Rick]

BAA electronic bulletin No. 00310   http://www.britastro.org/

Comet 2007 F1 (LONEOS) is inching its way into the evening sky for UK observers.  Currently around magnitude 7.5, it may reach 3rd magnitude by the time it reaches perihelion at the end of the month.  Despite this it is not going to be easy to see as it remains quite low down, and you will need transparent skies and a clear horizon to spot it.  At the moment it is slightly better placed for early risers, lying in the constellation of Coma Berenices.  On October 20 it passes about 4 degrees below Arcturus, and could show a short tail.  By then it is quickly moving south and will be gone from UK skies by the end of the month.  It is intrinsically quite a faint object, and may not survive perihelion.  Sometimes such small comets disintegrate and this could give rise to a short lived rise in brightness, so it is worth attempting an observation when you can.  There is a finder chart on the Section web page at http://www.ast.cam.ac.uk/~jds. The comet was discovered on March 19 during the Lowell Observatory Near Earth Object Survey, with Peter Birtwhistle being one of the first observers to confirm that it showed cometary features.

All observations, whether by DSLR, CCD or visual, are welcome.  I would particularly welcome more visual observations, as there are remarkably few visual observers active in the UK.  There is help on how to make visual observations in the BAA Guide to Observing Comets, which is available from
the Office.  Magnitude estimates are quite hard to get used to making, and are rarely as accurate as variable star estimates, however they can be scientifically useful.  If you make regular estimates during the apparition the random scatter averages out, and the value for the absolute magnitude (which gives an estimate of the size of the nucleus) becomes accurate to a tenth of a magnitude.

Jonathan Shanklin
Director, Comet Section

Head of Meteorology and Ozone Monitoring Unit
British Antarctic Survey, Madingley Road, Cambridge CB3 0ET, England
http://www.antarctica.ac.uk/met/jds
http://www.ast.cam.ac.uk/~jds