More 46P...

[Hallingskies]

Subframes:70 x 30s luminance, 20 x 30s each for RGB (for comet, same again for stars).

In this instance I guided on a star rather than the comet, limiting exposures to 30 seconds to avoid smearing out the comet given its rapid proper motion.  I tried some longer exposures with guiding on the comet nucleus, but the subs were plagued with gradients and noise: I think some high cloud had set in.

Using the sigma stacking function in Astroart, and "one star" alignment gave an image of the comet with star trails virtually eliminated. The LRGB stack showed the bright green colouration of the comet itself. I layered the RGB star stack (taken when the comet had drifted out of the field of view) over it to give coloured stars in the final image.

Below is an animation using the 70 luminance frames from above, showing the comet moving against the sky background.

This 3 second GIF shows the comet's movement between 19.07 and 20.01 GMT on December 12th, 2018, over a span of about 9 arc-minutes (about a third of a full moon diameter). The comet appears to graze the 9.7 magnitude Hipparcos catalogue star HIP 16342.

[dweller25]

Fantastic

[Hallingskies]

10 minutes ago, dweller25 said:

Fantastic

Thanks, David.  LRGB with a mono CCD is definitely a bit of a faff for fast moving comets.  It was the first time I had tried it and there is a lot to be said for DSLRs/OSCs....?

[Maxrayne]

Excellent work. She's a fast one looking at that 

[paul mc c]

Nice one,waiting on a clear bit here...