First time out

General discussion about StarTools.
rpsfam1
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Joined: Mon Oct 03, 2022 6:40 pm

First time out

Post by rpsfam1 »

Hi Everyone,

I will be doing some EAA tonight using my asi294mc-p and SharpCap. Do I understand correctly that I need to save my short exposures as RAW files to get the best results from StarTools? I normally do live stacking in sharpcap and it gives me several options for saving my captures and want to be sure I choose the correct one for StarTools.

Thanks in advance

Patrick
decay
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Re: First time out

Post by decay »

Hi Patrick,

welcome!

I don't know SharpCap, but you're right about the format of your shots: it's generally recommended for AP to save the single shots in RAW format to get the best quality for stacking. The output of your stacker should be in FITS format if possible. If I understand correctly, SharpCap already does the (live-) stacking? Then the output should be FITS.

If you like have a look at this documentation:
https://www.startools.org/links--tutori ... od-dataset

Good luck and let us know how you go on!

Best regards, Dietmar.
Mike in Rancho
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Re: First time out

Post by Mike in Rancho »

Hi Patrick,

:text-welcomewave:

Like Dietmar says, I guess it depends on what your question is as to the right guidance. If you mean you want to post-process the live stack results from SC, then yes save as the deepest quality (at least 16 but hopefully 32 bit) FITS you can, though TIFF might be possible also. Some TIFFs may not open in ST, so you'd have to do a quick test maybe.

However SC may allow, save the linear stack, with no stretching/STF applied, no white balancing or color correction, and so on.

If you are looking to save out individual subs, then yes a RAW and undebayered format is preferred, which may in fact be FITS, preferably 16-bit. You would then use a pre-processing stacker (there are many options) to calibrate those subs with darks, flats, and dark flats and stack them. Follow the ST stacking guidance from the link Dietmar provided depending on the stacker utilized.
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admin
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Re: First time out

Post by admin »

Further to the excellent advice here, one of the reasons why you would want to avoid live stacking (if you can), is that the live stacker can only use stats from whatever has been coming in.

A post-acquisition stacker can gather stats on all frames that have come in, in its entirety, and make decisions based on that whole. Those decisions will always be better / more informed / accurate. Therefore the stacked dataset will almost always be of better quality, and therefore you will be able to get more detail out of said stack.

Hope that helps!
Ivo Jager
StarTools creator and astronomy enthusiast
rpsfam1
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Joined: Mon Oct 03, 2022 6:40 pm

Re: First time out

Post by rpsfam1 »

Thanks to all for the help and advice! Looking at my sharpcap capture folder, it looks like SC saves my images in 4 ways:

1. the individual frames are saved as .png
2. a 16 bit RAW Stack FITS
3: a 32 bit raw stack FITS
4. and "save as viewed which includes all the histogram adjustments I made - those seem to be .png files as well.

If I understand the advice here, the best data for star tools to process is RAW and unstacked? so if Im doing EAA I should do one set of images for real time viewing (live stacked) and then another set for Startool processing (raw and unstacked). IS that right?

Thanks again for the help

Patrick
decay
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Re: First time out

Post by decay »

Hi Patrick,
rpsfam1 wrote: Mon May 29, 2023 8:42 pm If I understand the advice here, the best data for star tools to process is RAW and unstacked?
No, you need a stack as input for processing with StarTools. So you could use (2) or better (3) but this would imply the downsides of live stacking which Ivo pointed out in his post.

Best would be to find out a way to save the individual frames (1) not as .png, but in RAW format. Then you could stack them afterwards using a standalone stacker of your choice, e.g. DSS ore ASTAP or SIRIL.

As a first step I would suggest to give (3) a try as you probably already have such a stack. For next nights out you could try to find a way to save the individual frames in RAW format, as described above.

Regarding the processing in StarTools please have a look at this
https://www.startools.org/modules/intro ... uick-start

You will find some other (video-) tutorials and other helpful information on this page:
https://www.startools.org/links--tutorials

Best regards, Dietmar.
Mike in Rancho
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Re: First time out

Post by Mike in Rancho »

Yeah Patrick there's a few things you can do differently here, and one that you for sure need to do - which is consult the Sharpcap manual. ;)

You can certainly post-process the final live stack result (use the 32 bit FITS to open in ST) and I would think you will be able to enhance it greatly and reveal better detail than their auto-stretched image. But save that out also so you can later do a comparison. Keep in mind that if you intend to post your image, EAA forums may have rules disallowing the post-processed result. CN is that way. In the EAA forum you can only post your live stacked result with no alteration. The post-processed result would have to be posted in a DSO forum.

I don't have Sharpcap but I did take a quick look at the online manual. So, at first glance - you'll need to dive deeper plus test - it does appear that you can save out the individual subs during a live stack session, which you can then calibrate, stack, and post-process in the more normal DSO AP fashion. You do not want png's however. Those will either be debayered already, or they will be undebayered but many programs are not able to properly handle an undebayered png, since that is usually expected to be final image format. I believe I have seen this issue posted before regarding Sharpcap. However, from what I see you should be able to select FITS in the still image settings, which will carry over to the saving of the raw subs during live stacking.

At least I hope so! :D
rpsfam1
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Re: First time out

Post by rpsfam1 »

ahhh....I think I get it now! save the individual frames in ram 16 or raw 32 and THEN run them through DSS (the one I have) before beginning processing in Star Tools. I can do some live stacking for real time for viewing, then clear that out and start a new capture of individual frames to save for processing. Thanks for the great advice and help, guys!

Patrick
Mike in Rancho
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Re: First time out

Post by Mike in Rancho »

That's one way to do it, sure.

But I don't think you necessarily need to clear out your livestacking and start over. At least if your subs have reasonable exposure that would work for both. Thus, as I understand it, you can save out the raw subs simultaneously with your live stacking. That way you would be able to get both, and even be able to compare on the same lights subs - Sharpcap's own final livestack image, the saved 32-bit livestack but then post-processed in ST, and the individual light subs, calibrated and stacked in a stacking program.

Again I don't have Sharpcap and have barely looked over the manual, but that's what it seems to say to me. :confusion-shrug:
happy-kat
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Re: First time out

Post by happy-kat »

I've used sharpcap 4 pro and in the settings I save the files from the live stream as fits to post process later (DSS startools) if I want whilst also having live stacking for viewing straight away
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