Poor weather and sky placement meant that I only got one shot at PANSTARRS from my observatory location (I did get some results with an Astrotrac). So here it is and the bright planetary nebula NCG 40 was an added bonus.

This was taken in the early hours about 90 minutes before dawn just after the comet had risen above my trailer roof. This was my last outing with my 10 year old GM8 mount before switching to a 10Micron mount. The high northern declination of the comet meant I could go unguided for 5 minute subs without trailing or loosing sub frames, Compare this to the 10Micron which can go unguided for far longer at the celestial equator!

The short imaging time and wide fan shape of the comet lead to using a new processing technique. I did the usual kappa-sigma (kappa = 1.05, iterations 15) on star aligned and comet aligned images to try and isolate the stars and then the comet.

Star isolation with the huge fan tail was not possible but the blurred trailing edge of the comet was removed. The rough trailing edge around the nucleus gets naturally repaired during final compositing.

The comet aligned image was heavy streaked with star remnants (small movement of the stars in 90 minutes doesn't give enough information for good removal) so I used a reverse gradient removal technique to clean the image up. That is I cloned the streaked "comet only" image, applied a "dust'n'scratches" filter in Photoshop to reduce the streaks at the cost of blurring the comet. I then subtracted the original image from filtered image to give an image containing only the streaks (which are slightly blurred by the filter action). The "isolated streaks" image was then repaired around the comet nucleus (it was cloned out with background - the blurring action means there is a small difference in the nucleus area - which we are not interested in - so we remove it). Then the isolated streaks is subtracted from the original "comet only" image. The result does not completely remove the streaks but they are nicely smoothed out.

The compositing of the treated "comet only" image with lighten blending over the treated "stars only - mostly" image is effective and the blurred streaks merge in well with the original stars that caused the streaks. The comet nucleus and tail areas blend over and hide the edges eaten away in the "star only" image.

Version B: Added colour enhancement of bright stars