Not sure if this is the right place for this discussion. Regarding shooting calibration frames (darks, flats, and bias), any hints or ideas as to the best way to takes these Frames? I believe I know the best way for flats (i.e, white t-shirt over the opening of the scope, etc) but what exposure time (1s, 2s, 10s, etc). Regarding darks, I believe they should be on the same exposure time and temp as with the light frames. What about the bias? As I understand, bias do not depend on temp nor time exposure, so are 1 second bias frames adequate?
Sorry for all the questions, but calibration frames info is all over the place.
Hey Rudy, no problem!
Here is a quick rundown on how to take calibration frames:
DARKS:
- Same exposure time as the Lights
- Same temperature as the Lights
- Cover your sensor so no light can reach it
FLATS:
You got this one right, as for the exposure time, you will need to run some test shots and look at the histogram. Ideally, you'll want the histogram peak to be in the center. Taking longer or shorter exposures will move that peak left or right. Do your best to center it, then launch your series.
BIAS:
- The fastest possible exposure time your camera will allow
- Same temperature as the Lights
- Cover your sensor so no light can reach it
We only take BIAS frames with our DSLR camera, as it doesn't really matter that much with dedicated astrophotography cameras (well, from what we learned).
Hoping this helped,
Antoine
I have a ZWO CMOS camera so I will skip the bias frames. Is the Histogram measure through the software you use to take the exposures? I am using APT.
Thanks for the great feed back.
We use SGP and sometimes the ASIAIR. They both have a histogram display. APT should also have one for sure :)