[BAA Comets] Comet C/2012 S1 (ISON)

Andrew Robertson alphacentauri at tesco.net
Fri Nov 15 11:04:34 GMT 2013


Morning all,

Wonderful visual view this morning. My local forecast here in Norfolk was
for cloud slowly receeding as morning came. Set my alarm for 4am but only
bright stars overhead could be seen, I layed in bed for a while thinking
about whether it was worth getting up but had to go for it in the end. By
4.45am I could see brightish stars low down in the ESE. Once Porrima became
prominent I knew it was 'on'. However there was still cloud low down which
started thickening but by 5.10am it was clearing again. Sweeping below
Porrima with 8.5 x 50 binoculars I saw it as a slightly fuzzy star (5.20am).
I did consider that it might be a faint star 'fuzzed' out due to thin cloud
but comparisons with Theta and Chi Virginis either side of it confirmed
their star like nature as opposed to ISON which clearly had a coma around a
stellar core. Brilliant! - Two days earlier on Wednesday morning I could
only just see it in 15 x 70 binoculars with nothing in the 8.5 x 50's so
clearly it has brightened.

In the Vixen 102mm Flourite apo wonderful views changing between a 40mm
Pentax e/p (x22.5 and 2.9 deg FOV) and a 27mm Panoptic (x33 & 2 deg FOV). A
bright stellar core with a prominent coma around it and a long thin tail
extending about 3/4 of a degree visually in the still 'claggy' skies (always
hard to define where these end visually).

In the 12" Mewlon D-K at x90 it was superb! Just what observing comets
visually is all about, a really bright nucleus and long thin prominent tail.
If I'd had the time I would have sketched it but it was 5.45 am now in a
brightening sky with the view dimming considerably as cloud started rolling
in again. For once, a clear window at just the right time!

Might get another chance tomorrow morning, the almost full moon sets at
5.50am but it is at the opposite end of the sky so hopefully will have
minimal effect - I'll just set my alarm for 5am instead.

Andrew Robertson




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