Wirtanen and Arp

[petevasey]

Last night (17th Jan) the comet was due to pass very close to the interesting 11th magnitude Polar Ring galaxy Arp 336 (NGC 2685) in Ursa Major.  I kept my fingers crossed for a clear sky in the small hours (Moonset was not until 4 am) and for once the sky gods smiled on me and after a snowy cold front passed through it was beautifully clear for a couple of hours.  I used my Canon 700D on my 10" RC scope (2000mm fl) to try for some galaxy detail with a succession of 5 minute subs - any longer would show too much movement of the comet at that focal length.  Guided with a Lodestar on a Celestron off-axis guider.  And this was the result.  The galaxy really needed much longer exposures, but the polar ring is just visible.   The two distant edge on galaxies in the lower part of the image are (reading down) PGC 25034 (mag 17.1) and PGC 25046 (mag 16.7).  16 x 5 minute subs, darks, flats and bias frames also used.

I already had an image of Arp336 from 2008 and there was enough detail and nearby stars to position it exactly in the second image.   But I realise that because the galaxy image was captured some years ago, that version cannot be submitted to the competition - I just include it out of interest.

Cheers,

Peter.

 

 

[petevasey]

I've now produced an animation of 16 frames showing the movement over 90 minutes. There is a slight jump, a couple of the originals were unusable.  Small version below, a larger version is too big at 2.68 MB for the size limit, but can be found here.  As you can see by tracing the path back, the coma would have passed over the galaxy.  A pity there was a bright Moon - if it had been New, with full darkness at 6.30 pm on 16th instead of 4 am on 17th, the comet would have been at its closest to the galaxy at the start of the imaging run and I would have many more exposures and a much longer animation.

Peter

[Scooot]

Fantastic. Great image and animation.