Dark frame Queston

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
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Capesky1
Posts: 11
Joined: Sat Jan 04, 2020 5:26 pm

Dark frame Queston

#1

Post by Capesky1 »

Is it possible to take one dark frame and store it in the Dark frame library and then make copies ( adding a sequential number after each file name).
This would seem to save a lot of time when taking multiple dark frames.

Also, how would this effect the live stack process ?

Thanks,

Charles :D
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Menno555
Posts: 1053
Joined: Mon Apr 20, 2020 2:19 pm
Location: The Netherlands
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Re: Dark frame Queston

#2

Post by Menno555 »

Hi Charles

It would save time yes :) but sadly it doesn't work that way. If you make copies of that 1 file, each copy is exactly the same and the master dark calibration file would look the same as each dark frame.
And the whole purpose of multiple dark frames is to get dark frames that each differ, so that when the master dark calibration file is made, you get an "average".
In each dark frame there can be horizontal lines for example. But in each dark frame those lines are not (exactly) in the same place.
Or with so called "amp glow": this also differs slightly in each dark frame. And also jumping pixels.
All these things are stacked together as it were into 1 master dark calibration file and this is used to "filter" all that out of your exposures.
And yes, that can take time to make. For my camera and way of processing, I always take 30 dark frames. For 30 second exposures that is not so bad cause that is only 15 minutes (900 seconds). But I also do 600 second exposures and that takes 5 hours (this I don't use for live stacking of course :) ).

But that is something you should experiment with yourself. There are enough people who are content with 10 dark frames.

Menno
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