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ASI1600 flat darks library


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Just thinking out loud. I know it's better to calibrate flats with flat darks to match the flat frames with this camera. Given how short flats are, I try to keep them between 1-5 seconds, could I shoot a flat darks library? Say from 1s to 10s and use the nearest figure to the flats? Example, I shoot a load of flats at 3.25s. Could I calibrate these flats with a master flat dark of 3s?

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How many filters do you have? Why not time flats for each filter and then do master flat dark at that exact duration for each filter?

You don't have to build flat dark library in advance, next time you take flats for particular filter - just record used exposure and record flat darks at same settings. Keep master flat dark and next time you shoot flats for that filter - use same exposure length. If you have more than one scope with significant difference in flat exposure for that filter - just create one for each scope / filter combination.

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That's what I normally do Vlaiv but at 3am in the morning I'm keen to get everything in, especially if I want an hour or 2 sleep before work!! I have 7 filters. I use APT's flats aid to take the flats at 25000 ADU. Sometimes the exposures vary by a second or so depending on how bright the panel is. It's an Artesky panel with variable output. I have master darks, just thinking it would be handy to have master flat darks. Surely the thermal noise difference at those kind of exposures are minimal?

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Guess simplest thing is to try. There probably won't be much difference between using exact time, or 25% longer flat dark. Just remember what you've done in case you run into trouble with calibration, then first thing to do is matched set of darks.

Btw, darks can be done at any time, so it's not necessary to do them at the end of the session - just record flat duration and do matching darks tomorrow?

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1 hour ago, david_taurus83 said:

That's what I normally do Vlaiv but at 3am in the morning I'm keen to get everything in, especially if I want an hour or 2 sleep before work!! I have 7 filters. I use APT's flats aid to take the flats at 25000 ADU. Sometimes the exposures vary by a second or so depending on how bright the panel is. It's an Artesky panel with variable output. I have master darks, just thinking it would be handy to have master flat darks. Surely the thermal noise difference at those kind of exposures are minimal?

You can always do flats during a daytime...

As per variable panel brightness, - has it got FULL brightness option? so you would be able to dim it using sheets of paper and have the same level each time.

Edited by RolandKol
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59 minutes ago, RolandKol said:

You can always do flats during a daytime...

As per variable panel brightness, - has it got FULL brightness option? so you would be able to dim it using sheets of paper and have the same level each time.

I carry the mount and scope back into the house after each session so cant take the risk that a bit of dust might move and ruin an entire evening! I think I'm going to just shoot a flat dark library of 1s through to 8s and just use that. Will see how it works.

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If you keep the camera attached to the scope then you should be okay just taking flats and dark flats at a later time. Camera connected lens cover on scope then it sounds fine. Think of it this way, allot of people take flats, darks, dark flats and then use them for a good while before redoing. Then just think how long our lenses or open to the outside elements for when running an imaging session.

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