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In case anyone is interested, there is an article in Sky and Telescope on the mysterious ‘Cow’ transient that appeared six months ago. Therein are further links to the research literature (Open Access).
https://www.skyandtelescope.com/uncategorized/cow-celestial-event-puzzles-astronomers/
I agree with Andrew and Owen. For me, I found that once it had moved over the north sea into dark skies, I could star hop to it using binos. It has a very diffuse appearance which responds to averted vision. I have also used GOTO with my C8 and looked at it with my Televue 32mm plossl. Not an impressive object visually, but there.
I would suggest that you get a >10Ah power pack manufactured by Celestron or SkyWatcher or such like. Just check that it has the right 12V output sockets for your dew heater straps (but I expect you know this!).
I have a Celestron lithium mini-tank also – it is useful for illumination and USB charging, but no good for the more demanding peripherals!
Dominic, our wizard on all things IT (and other subjects), reported a while back that animated gifs are not supported on this site. You might be pleased to know though that the comet archive does support animated gifs. Michael Jaeger’s swooshing comet tails are a regular feature there. David S
Nice spectra, both. It is good to hear Robin that you can subtract the contribution of airglow and light pollution – if only we could all do that for all observation modalities! The comet is rapidly moving out of the worst light pollution for me and is now a) not a problem to locate in binoculars (albeit not impressive visually) b) a good imaging target with an extended coma within reach of my camera. I get a mag of 5, which is very close to Nick’s value (4.9).
Thanks to all the speakers and the technical people who put the material online – and of course the organisers too. David Swan
Hello James. I am a fan of imaging transients and noticed this one a few days ago on David Bishop’s website. IMHO it certainly is worth flagging this on the forum – as a (visible) PSN or SN in a Messier object does not occur that frequently. Great image! The weather where I am is atrocious. David
Peter Carson has managed to capture a much better image (see his member’s page). Nonetheless, under poor conditions (wind ESE – straight from sea towards scope (!), and lots of condensation on the corrector in misty air) I acquired five reasonably steady frames. Comphot estimate: mag 10.4 in photometric aperture of diameter 130arcsec – but take this with a pinch of salt.
As Nick has said, the orbit is obviously very well determined. I updated MPCORB in Astrometrica, and the comet was spot on the predicted position.
DDP tends to bloat the stars and make them furry. Here’s a clearer image with the ion tail quite distinct. 12 x 10s, midpoint 05:14:30.
Very nice. Hopefully I’ll be granted a half hour patch of clear skies in the morning some day soon. D
An excellent set of talks. Thanks to all the speakers and those involved in getting the content on the website. David
This is a good question – to which I can’t offer you a good answer! You might want to submit your question to the comet discussion list and Nick James or another will likely pick it up quicker.
I would say that if your plate scale is around 1 arcsec / pixel or below then you might as well 2×2 bin and use the mono pics for astrometry. I’m not sure what you should do if you are correctly sampling or are undersampling.
I look forward to seeing your colour pics of Wirtanen! I’ve just bought a Hyperstar (Christmas brought forward) to give me a wide field of view for the close approach.
Good to hear you are imaging 64P – it’s nice isn’t it? And 38P is moving to a better position.
David
