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Darks library, what about dark flats?


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Hi all.

I've created my own darks library for my ASI1600mm Pro.  Various gains and various exposure times all at -10 Celsius.

I'm just wondering what people do with them?  Once you've taken darks and processed an image you get your master darks.

Do you guys just keep the master dark, in a master darks library, or do you process your darks again each time you stack a new image?

I'm just thinking to save storage, could I discard the dark sub frames and just keep the masters?  I don't want to throw them away if that is wrong though.

Also, with this camera I take dark flats rather than bias frames.  Because the scope is covered, do I need to do dark flats each time I take flats?

I have an even illuminated flat box which I always use at the same exposure lengths.  I guess the only thing that could vary is the gain value.

I understand the need for flats every time you change focus, for each filter etc., but if I'm using the same exposure time can I just use a previous set of dark flats as long as the camera settings are the same?

If this is possible, can I then create a dark flats library for any difference in gain values?  Not sure if I gain values affect dark flats though.

I've read that back, and that's a lot of questions!  All help greatly received.

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There is no need to re-do flat darks every time you do new flats provided the settings are the same. Flat exposure times are pretty sensitive, though, because the exposures are very short and the cameras very sensitive. A slight change in the brightness of your panel might need a different setting. If it doesn't you can re-use your flat darks.

I think gain settings will affect any kind of dark but I'm not a CMOS user.


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Thanks Olly

I've used the APT flats aid to get to the average ADU exposure times.  The flats panel has worked pretty consistently so far.

I think you're right about the gain having to be the same.  Astro Pixel Processor has thrown a wobbly in the past when I've used  a different gain value flat to dark flat.

Do you keep your old dark frames, or just the masters?

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14 minutes ago, Jammy said:

Thanks Olly

I've used the APT flats aid to get to the average ADU exposure times.  The flats panel has worked pretty consistently so far.

I think you're right about the gain having to be the same.  Astro Pixel Processor has thrown a wobbly in the past when I've used  a different gain value flat to dark flat.

Do you keep your old dark frames, or just the masters?

I only keep the masters. I have enough darned files as it is!


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