I’m often watching or reading guides in the gaps between clear nights so inevitably I have new things I want to try on every image.
For this image that new process was a more structured method for selecting my best subframes for stacking. My usual approach was to blink through them after which I would remove any that had obvious star trailing, after that I would register everything in DeepSkyStacker and remove a handful of subs with the lowest scores.
Here I did the same but also made use of PixInsight’s Subframe Selector process which performed a proper analysis of my subs. I then removed any outliers based on FWHM, median, stars and eccentricity and stacked what remained.
Unfortunately I had to throw out an entire night as the FWHM of all of those subs was well outside that of my best frames, I suspect I wasn't very well focused for that night. I started with 16.5 hours of data but only stacked 10.5 of the best. I did do a quick test and stacked all 16 hours just for comparison. As expected it was cleaner in terms of noise but the smaller stack was noticeably sharper, the improvement in the stars was particularly noticeable.
For most of my images I try to find examples taken with similar equipment to serve as inspiration and as a guide. For this it was
@Lee 's image (
https://astrob.in/swc0q9/0/) which I really liked.
As far as processing goes I found the tricky part was striking a balance between reducing the dominance of the starfield without ruining the emphasis of M35 and NGC2158.
This was also first light for a new filter, the Antlia ALP-T. It's a dual band filter with a similar bandpass to the popular L-Extreme but at 5nm rather than the 7nm of the L-Extreme.
Thanks for looking all.
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