6 replies to this topic

[mbuto]

Howdy,

 

Just wondering if you need to do a complete set of darks and biases on every night you are imaging the same target? I believe you can use a single set of flats.

 

Thanks,

 

Mike

 

[Alex McConahay]

You can reuse darks and biases for a while (months). This assumes the same temperature.

Flats should be taken every time you take your rig apart and reassemble. And with every different rotation. They should be taken maybe once a month or several months depending on your dust conditions if you have a permanent setup.

Alex

Edited by Alex McConahay, 06 August 2022 - 02:33 PM.

[Ken Sturrock]

This one gets discussed pretty regularly - think it through. The dark captures camera-specific patterns which you want to remove from your image. So long as the camera settings and temperature remain the same, the pattern will also remain the same.

[mbuto]

So by temperature the same, do you mean +/- 1 degree? 5 degrees? 

[DirtyRod]

So by temperature the same, do you mean +/- 1 degree? 5 degrees? 

I have dark libraries at 0C and -10C. Most people doing AP use cooled cameras so you can set the temp and keep it with a few degrees of the target. I use 0C when it’s summer here in AZ otherwise -10C for all DSO imaging. Generally if you are within 5 degrees the calibration frames should work. 

 

As mentioned, you can reuse your dark libraries. I reshoot mine every 6 months but I take flats every session. I do reuse flats for multiple nights if the camera, filter, and imaging train have not changed.

Edited by DirtyRod, 06 August 2022 - 03:45 PM.

[mbuto]

Thanks all!

[Ken Sturrock]

A few degrees is probably fine. Is this an un-cooled camera? That would make your life harder but you should be able to scale the dark OK using the "warmest/noisiest" dark frame that you have and a bias frame.