As the weather's gone from cold and grey, to cold, grey, wet and windy, it was time for another re-processing session! Here's the Rosette nebula from a few separate sessions (done by copying the files back to the #SeeStarS50 to restack). Siril, Graxpert, Photoshop 453x10sec subs #Astrophotography - ThreadSky

helenlittle.bsky.social • 9 days ago

As the weather's gone from cold and grey, to cold, grey, wet and windy, it was time for another re-processing session!
Here's the Rosette nebula from a few separate sessions (done by copying the files back to the #SeeStarS50 to restack).
Siril, Graxpert, Photoshop
453x10sec subs
#Astrophotography

Comments

dazza1639.bsky.social•7 days ago

Another great shot Helen 👍

helenlittle.bsky.social•7 days ago

Thanks Darren! 😃

elliottucker.bsky.social•7 days ago

That’s fantastic! Is it a mosaic? You seem to have more rosette in it than I can get.

helenlittle.bsky.social•7 days ago

Thanks Elliot! Yes, it's a mosaic 🙂 Here's what it looks like after using 'Deep Sky Stack' in the SeeStar (about 460x10sec subs):

elliottucker.bsky.social•7 days ago

Thanks! I'd never thought of adding back to the seestar to do the stack.

dobsonaut.bsky.social•7 days ago

Beautifully crafted, Helen! It's astounding how well the Seestar's stacking algorithm performs. Have you compared that result to your own manual stacking?

helenlittle.bsky.social•7 days ago

Thank you Matthias! The Seestar certainly does a good job, and at the moment it's the only way I've found to restack all the mosaic files from several sessions. I think when Siril 1.4 is released that will be even better though. Here's a manual Siril stack (left) compared to the Seestar (right):

dobsonaut.bsky.social•7 days ago

In fact, I can't see any difference in the quality of star images between these versions! May I ask one more question: What do you mean by "the only way to restack mosaic files from different sessions"? Collecting subs over time and restacking them in Siril should be quite possible, shouldn't it?

helenlittle.bsky.social•7 days ago

Yes, it is possible, but at the moment (v1.2.6) Siril can't re-create a large mosaic if the subs at the edges don't overlap much with the reference image. So I can get a stack of the central part, but not the 'double width' of the x2 mosaic. Sorry, I'm not explaining that very well!

helenlittle.bsky.social•7 days ago

Another interesting comparison, but perhaps not very 'fair' as they're not processed exactly the same way. Left: a crop of the first image in this thread (seestar stack). Right: Siril stack of the same subs. Both denoise/deconvolution in Graxpert, further stretching, colour calibration etc in Siril.

helenlittle.bsky.social•7 days ago

There seems to be more detail in the one on the right, but I don't think that would be obvious on a small screen.

dobsonaut.bsky.social•7 days ago

Pixinsight offers a process "Mosaic by coordinates". By solving every single sub for its exact coordinates, you may even stack frames without overlap. It's sort of computationally "expensive", but very effective for "scattered" subs.

helenlittle.bsky.social•7 days ago

Unfortunately I don't have Pixinsight (can't quite justify the cost - yet!) but that sounds exactly like the new feature that's coming in Siril 1.4. Can't wait!

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