Comet Holmes

At our Friday meeting, in the planetarium, Pat Walker kindly mentioned that he had seen in the Heavens above website that comet P/Holmes had suddenly brightened from 17 th mag to 2 nd mag! At the moment the comet is in Perseus north of Alpha Persei.

Sunday was very wet (good for the plants we had put in!) However by 21.00 (GMT) the bright waning gibbous Moon was bright in the eastern sky, so I decided to take a look for the comet using my 15x50is Canon binoculars.

Shortly after sweeping in the area, I encountered it – what a sight! – I quickly phoned my friend Newark in North Watford to alert him and went back to make my observation.

Comet Holmes is very bright – the unaided eye shows it as a first magnitude star, in the 15x50s I saw a circular patch about 50% larger than the apparent size of Jupiter, sharply defined, the inner third much brighter. A slightly darker band separated it from the outer ring. In colour it looks like the planet Uranus – yellow-green.

This is a very easy object – you don’t even have to be dark-adapted to see it!

What could have caused this brightening?

Update
The week following my first observation of the comet every evening was clear. I observed it with binoculars every night and it remained much as I first described it (If you can imagine the Eskimo nebula in Gemini seen in a 6 inch telescope, only viewed in binoculars, you’ve got the picture).

However, on Thursday 1st November, I used my 8.5inch reflector at x48 to examine the comet. The brighter centre area is somewhat offset from the centre and a very small bright dot (the nucleus) is to one side of the centre of that. The outer ‘haze’ fades fairly sharply into the sky background – except the region opposite the nucleus – so we are seeing the comet from an obtuse angle.

I –and my friend Newark in North Watford, have continued to observe this comet and have noticed that the contrast between the bright central zone and the outer haze is diminishing and the sharp ‘edge’ between it and the sky is less obvious. My last observation was Thursday 8th Nov.

If you get a clear night, do have a look at Comet Holmes. It’s not as bright as it was and it is slightly closer to Alpha Persei but it’s still worth a look.

We are seeing Astronomy happening in real time here!

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