[BAA-ebulletin 00771] Comet 2012 S1 (ISON)

[BAA electronic bulletins service]

Comet 2012 S1 (ISON) has brightened dramatically by over two magnitudes and is now 5th magnitude or brighter.  It is not clear whether this brightening represents a terminal disruption or a rejeuvenation of the active areas.  Only further observation will show which is the case.  On the one hand it may continue to show a well condensed inner coma, on the other hand the coma may steadily become more diffuse.  The brightness evolution is uncertain.

The inner coma region is particularly important, and imagers need to take many short exposures in order to avoid saturation of features.  These can be stacked to show detail both in the inner coma and the tail region as appropriate.  Many recent images are over-exposed in the inner coma region.

Comet 2013 R1 (Lovejoy) is nearing is likely peak brightness at around 5th magnitude.  Both comets are best seen just before dawn.  Unfortunately high cloud covers much of the UK (despite the weather forecast showing clear skies in the south) and this is likely to prevent observation.  Scotland looks better placed on Sunday morning, whilst clear skies may be more widespread on Tuesday morning.

Further information on the comet is on the Section web page at http://www.ast.cam.ac.uk/~jds

Jonathan Shanklin
Director, Comet Section

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