Comet Leonard from 7.12. Version with stars, with trails and an animation of raw subs.

[ONIKKINEN]

First with trails

With comet and stars (and some PGC fuzzies here and there in the background)

And finally the animation from the best subs, about an hour or a bit more i think.

 

Shot on the 7th of December between 2:46 and 4:14 UTC, except for the animation which i believe is from somewhere around 3:10 to 4:14. Shot with an OOUK VX8, Maxfield 0.95 coma corrector/reducer and the RisingCam IMX571 OSC with 30s exposures. There are some gaps due to lost subs unfortunately, but mostly uninterrupted. Quality of the subs was perhaps the worst i have taken so far due to Leonard being low in the sky and towards magnitude 17.5-ish skies. Also, since everything sits on top of the absolute marvel of modern precision engineering: The Skywatcher EQM35, guiding was and never is great to southern targets like this was. Most subs somewhere around 2 arcsec RMS, some worse than that. The gaps in the sequence are from subs bad enough to have no usable stars for stacking.

The trailed version is pretty straightforward, just stack on the comet with average combination in DSS.

The second version is far from straightforward as DSS just does not stack the image to comet AND stars, its only one or the other. Trying to stack with comet and stars alignment only works for the green channel for some reason? Red and blue channels are trailed like the image was only stacked on the comet, leading to green uncolorcalibrateable stars. So it is a mixture of a comet stack and a starstack with aggressive kappa-sigma clipping to delete as much of the comet as possible. Then some layer trickery, background copying, starless layer tricks, healing brush etc, all the "bad practices" you can do for astrophotography processing and there it is. Could be better, or worse so i think its acceptable.

The animation was also interesting to do as i couldn't figure out an easy way to do this. In the end i ended up taking the calibrated subs from DSS, processing them with a few simple adjustments in SIRIL and saved a PNG of the autostretched preview. Easy and quick to do for the 120 or so subs i chose for this. PNGs put into ASTAP for blinking and alignment, of which i then took a screen recording of . There is probably a tool for this somewhere in the internet but i couldn't easily find one that is not PixInsight.

First time processing/shooting a comet so a lot to learn, feel free to comment/critique if you want to.