That is why I say that one always learns something new in each project. This is the experience that both Maurizio and I had capturing this awesome visitor C-2022 E3 ZTF.

The session.
Maurizio managed to do this session in a mountain place for try to get the best of this comet during those days that was more close to us.
On that occasion he managed to make around 453 frames of which 53 were discarded and 30 are when it was already dawn and at some point they will be processed.

While taking the first test photos Maurizio realized that the exposure time was too long because the comet presented a front line despite the guidance. By then the comet had a high speed and the 60 sec that he had set were too much. So he did a 45 sec first set and then tightened it up to 30 sec with ISO 2000 for the rest of the session.

However, during the session, he had to reposition the comet framed four times between the comet run and the mount flip.

The proces.
I had two stack groups, one with 75 frames and the other with 338 frames. I tried to make a normal first stack with 338 frames for to have the star base. My surprise was that the final stack obtained was both the stars and the comet clear, what? I was amazed because I had never used this DSS modality before and I didn't remember having touched any parameter out of the 'normal' but it was what I got...Despite placing an acceptance of 90% of the best frames, the program took into account only 168 frames, which is much less than 90% placed...?

Probably the important thing about that stack after doing a quick processing was to observe for the first time the frontal fan and a filamentous structure in the tail that also did not make it straight but deviated it, that made us very excited. I proceeded to make another stack with the same group of frames doing a 'normal' stack. The program rejected half of the frames and only considered the first 162. At least I was able to use it to make the star base. I realized that the frames of the sequence that it did not take into account were those of the second and third reposition.

I had to divide the 338 frames set into three groups: 180, 34 and 122 frames. Once this was done, I tried to do the comet-startrail stack with each subgroup and for some reason, the program kept always presenting me an image with fixed stars and the smeared comet.

Finally, I reminded myself of going to read the latest messages from the specialized DSS group and indeed the developers commented that there is a bug in the comet-startrail modality when you do not set to use 100% of the frames... and for this reason the program refused to do the proper stack... Fortunately they are working on it and the correction will be incorporated in a new revision of the latest version that they just released.

Well, one takes many things for granted, and now I realize that every time I've done that type of stack I selected the100% because the worst frames had been previously discarded. When one is not ordered in the workflow...

Solved the 'issue' stack, I took into account the tips commented by Dan Bartlett for how to enhance the details in the comets,  and the set of 180 frames was split in five subsets. Finally I could have the five stacks files for work after on Ps, making a final blend with a result that showed many details of the comet and especially the tail (Revision B and E).  Same with the other two set group of 35 and 75 frames.

The other thing I notice is that the first  40 frames of the group 180 frames, are the ones that provided better details of the tail than the rest of the subsets, although each one presents a different accentuation facet along the tail and especially after the 'inflection'. Very interesting to observe this behavior in such a short time and witness how the comets 'evolve' as they lose or disperse the material of which they are composed.

The session carried out by Maurizio was fully processed and completed but in the end new additional and more refined stacks obtained through a new workflow made in Siril were incorporated.

In recent days,  Rich @DeepSpaceAstro  made a video where he propose a very good workflow managing to make the comet stack starless producing a fairly clean image and that it preserves its details (Read carefully the first message on pin). He has made several informative videos for those interested in using the great tools that Siril incorporates.

Nico Carver has also released recent videos regard Siril that provide excellent information on the tools and their uses in the new version released these days.

The images in the revision part are cronologicaly

Rev A First image session 00:16-1:23 am 75 frames
Rev B Second image session 1:36-3:53 am 180 frames
Rev C Second image - comet star-trail
Rev D Third image session 3:59-4:35 am 34 frames
Rev E Second Image session - incorporate some luminance.

The fourth and last image compose by 122 frames of this series will be published soon.

We appreciate your visit and may you all have good weather and Clear Skies!

Processed February 2023

https://twitter.com/AstroOtus/status/1630639273467625485