Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Multi-night imaging

  • Please log in to reply
6 replies to this topic

#1 mbuto

mbuto

    Sputnik

  • -----
  • topic starter
  • Posts: 35
  • Joined: 11 Nov 2021

Posted 06 August 2022 - 02:14 PM

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

 



#2 Alex McConahay

Alex McConahay

    Voyager 1

  • *****
  • Posts: 11,575
  • Joined: 11 Aug 2008
  • Loc: Moreno Valley, CA

Posted 06 August 2022 - 02:31 PM

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.


#3 Ken Sturrock

Ken Sturrock

    Cardinal Ximenez

  • *****
  • Administrators
  • Posts: 11,848
  • Joined: 26 Sep 2009
  • Loc: Denver, CO

Posted 06 August 2022 - 03:07 PM

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.



#4 mbuto

mbuto

    Sputnik

  • -----
  • topic starter
  • Posts: 35
  • Joined: 11 Nov 2021

Posted 06 August 2022 - 03:30 PM

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



#5 DirtyRod

DirtyRod

    Viking 1

  • *****
  • Posts: 827
  • Joined: 23 Mar 2021
  • Loc: Arizona

Posted 06 August 2022 - 03:38 PM

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.


#6 mbuto

mbuto

    Sputnik

  • -----
  • topic starter
  • Posts: 35
  • Joined: 11 Nov 2021

Posted 06 August 2022 - 03:44 PM

Thanks all!



#7 Ken Sturrock

Ken Sturrock

    Cardinal Ximenez

  • *****
  • Administrators
  • Posts: 11,848
  • Joined: 26 Sep 2009
  • Loc: Denver, CO

Posted 06 August 2022 - 04:53 PM

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.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics