Muktiple nights stacking in Sirilic - using stacked file?

[aeksora]

Hi all,

I am pretty new to Astrophotography and I recently wanted to stack multiple nights of data in Sirilic. It went pretty well, but the stacking took almost 4 hours because of the amount of images. If I wanted to add another night of data, can I just take the file that came out when I stacked previously and use it as a light without any calibration frames or do I have to use all lights from the previous sessions again? Using just one file for the previous sessions would significantly reduce the time I have to wait for it to stack.

Thanks in advance!

[michael.h.f.wilkinson]

I do not know about Sirilic, but I have stacked results from different sessions in Astro Pixel Processor without issues. Note that I stacked the non-stretched versions, with background subtracted.

[ollypenrice]

I'm not quite sure what you're asking. Are you suggesting that you consider your first stack as one light which you then put into a set of new lights as if it were one new sub? If so, you can't do that.

To save time, you can make a new stack and then combine that with the existing stack, weighted according to exposure time. If your first stack had 2 hours and your second had 1 hour, you'd weight them 2 to 1.

Olly

[Elp]

You stack the stacks (as above with weighting which is something I'm yet to try myself). You load each stack as if it were a set of lights/darks/etc so if you've done say five imaging sessions you'll only have five files in the list, then go through the process of registering then stacking. It's quite quick this way as the long work has already been done. Each stack file needs to still be in a linear state before doing this (as it was stacked not histogram stretched, I think you may be able to perform background extraction on it and some other things prior but little else).

[PhilB61]

I have recently started stacking multiple nights data, but doing it manually in SIRIL rather than Sirilic. What I do is take the pre processed lights from each night and put them into a new sequence. Then register the whole combined sequence, review under the plot tab. This allows me to cull some of the outliers which I may have left in a smaller stack. Then stack as normal which also allows for all the subs to be normalised. Obviously if you have already registered then you will be doing it again but I have tried to avoid that. I have found SIRIL to be very quick when pre processing/registering/stacking 250+ light files plus calibration frames from my AA26C (IMX571). I can't imagine how many subs you would need for it to take over 4 hours.

[Elp]

I thought it's the same software?

[PhilB61]

Sirilic is a separate front end gui for Siril, which I believe helps automate the use of scripts. Both use the same processing "engine" As I've always processed with Siril manually that's what I'm comfortable with.

[ollypenrice]

If you don't mind doing it this way, you can calibrate and save the individual subs without stacking them and then stack these calibrated files without any further calibration.

Olly

[ONIKKINEN]

On 20/02/2024 at 16:39, PhilB61 said:

I have recently started stacking multiple nights data, but doing it manually in SIRIL rather than Sirilic. What I do is take the pre processed lights from each night and put them into a new sequence. Then register the whole combined sequence, review under the plot tab. This allows me to cull some of the outliers which I may have left in a smaller stack. Then stack as normal which also allows for all the subs to be normalised. Obviously if you have already registered then you will be doing it again but I have tried to avoid that. I have found SIRIL to be very quick when pre processing/registering/stacking 250+ light files plus calibration frames from my AA26C (IMX571). I can't imagine how many subs you would need for it to take over 4 hours.

This is what i would do if i were the OP. Manual stacking ensures you get the best image out of the hard work spent capturing the data.

Siril is very close to being SSD write speed limited for registration and image analysis, at least on my system. My biggest stack was 1519 subs at 300mb each, to a total of 455gb and took a few hours, but not as long as 4.

With an old HDD some stacks might take a while, but shouldnt ever run into multi-hour stacking ordeals with modern PCs.