Astroart Forum

This is an integration of 19 x 60sec exposures from Jan28/29. I used the 'Follow minor planet' feature while Sigma Sum stacking with 'no alignment' selected.
10in F5 SCT, Orion SS Pro 6mp OSC camera, CEM60 mount.

Nice. Good work at a good time for the comet! A walkthru of your steps would be nice. I have been using Manual stacking at high mag relying on the "centroid." Up to 138 images at 40s on 16Mp cam. Gets old:)

gregor wrote: ↑

07 Feb 2023, 17:14

Nice. Good work at a good time for the comet! A walkthru of your steps would be nice. I have been using Manual stacking at high mag relying on the "centroid." Up to 138 images at 40s on 16Mp cam. Gets old:)

I'll have to refresh my memory and I'll post the workflow later today.

gregor wrote: ↑

07 Feb 2023, 17:14

Nice. Good work at a good time for the comet! A walkthru of your steps would be nice. I have been using Manual stacking at high mag relying on the "centroid." Up to 138 images at 40s on 16Mp cam. Gets old:)

I guided on the comet using a guidescope aligned with my imaging OTA.
I checked the 'plate solve' box in the Sequence tab so that an accurate RA and Dec was written into the Fits header for each 60 sec image.
When I preprocessed the stack of images I used the 'Sigma Sum' option for stacking.
I used the 'none' option for alignment and the 'Follow 'Minor Planet' checked with using the 'Motion, WCS' option.

AA8 then calculates the movement from image to image and keeps the centre of each frame aligned. Since I guided on the comet this automatically aligned the comet on each image frame during the stacking. The 'Sigma Sum' stacking algorithm rejects pixels that don't repeat from image to image and thus eliminates the stars since they move from image to image.

Great use of sigma sum! I never though of using it like that!
I have 90 30 sec images I was going to make into a video, but will definitely play with the sigma sum trick.