Multiple nights calibration frames

[steviemac500]

If I'm taking exposures over a few nights, when do I take darks and flats?

[Davey-T]

DSLR darks are best taken at around the same temperature as your light frames so anytime that the temp is about the same, best not to get too hung up on it as you have no control over the camera temperature. 

Flats need doing without removing the camera from the scope so if you can disassemble the kit but leave the camera attached you can do them at any time.

Dave

 

[steviemac500]

Dave thanks, what I meant was if I'm taking a set of lights tonight, do I need to do a corresponding set of Calibration frames tonight and each extra night as well if I'm planning on exposing over a few nights or can I do a batch of them when I'm done to fit all of the exposures?

Steve

[Davey-T]

You can do the flats all in one batch as long as you can keep the camera attached to the scope and the focuser locked between sessions.

You can do the darks all in one batch trying to keep them around the same temperature as the lights or you can do stuff in software to scale them to approximate a match.

You could leave the camera running taking darks when you finish imaging.

Are you dithering ?

Dave

[steviemac500]

Davey, yes I'm dithering but I was going to take darks as well as a comparison. Thanks for the info. 

[zicklurky]

You can make a master dark and use it for a couple months as long as the temperature you took them at is around about the same as you're imaging.

Flats are a different story and need to be taken more frequently, as they are responsible for calibrating out dust bunnies. So if you're using old flats, and get new dust bunnies in your imaging train, these obviously won't calibrate out. Or if dust has shifted. Personally I take flat at the end of every session, it only takes 10 minutes.