Confused about taking darks, need confirmation

[Quetzalcoatl72]

I would take to take pictures with 2 different scopes in one night but using one camera. My question is do I have to do darks for both setups or can i just do them with the cap on the camera later with the cooler at the same temp? Also I already have darks took with both scopes from last week, can I just use those?

[symmetal]

The darks are purely related to the camera. As you have the cap on, the scope can't have any effect on the darks. Darks are often taken with the camera sitting on its own indoors, in the fridge. 🙂So use the same darks with any scope. As you say just the temperature, (and exposure) needs to match.

Your previous darks will be fine if they were at the same temperature and exposure. Usually it's common practice to take new darks every six months or a year just to take into account slight changes in the camera performance over time.

Flats are the only calibration frames which are specific to each scope setup.

Edit: You can use darks with exposures which don't match your subs if you enable dark scaling in your stacking program and have a master bias available, but as new darks are only taken very occasionally, you may as well have a set of darks which match the exposures you use for your subs. They should always be better than scaled darks.

Alan

Edited January 25, 2023 by symmetal

[Quetzalcoatl72]

3 hours ago, symmetal said:

The darks are purely related to the camera. As you have the cap on, the scope can't have any effect on the darks. Darks are often taken with the camera sitting on its own indoors, in the fridge. 🙂So use the same darks with any scope. As you say just the temperature, (and exposure) needs to match.

Your previous darks will be fine if they were at the same temperature and exposure. Usually it's common practice to take new darks every six months or a year just to take into account slight changes in the camera performance over time.

Flats are the only calibration frames which are specific to each scope setup.

Edit: You can use darks with exposures which don't match your subs if you enable dark scaling in your stacking program and have a master bias available, but as new darks are only taken very occasionally, you may as well have a set of darks which match the exposures you use for your subs. They should always be better than scaled darks.

Alan

Wow, thanks! I had a feeling I was doing something unnecessary, I still have to take my scope indoors to do the flats though. I have my askar attached to my ed80, it's the only way to mount it with what i have so I should do my lights with that first then the ED80 later depending on what's in the sky atm, like doing pleiades first then triangulum for instance. I only seem to get a few clear nights in the first 3 months of the year and nothing till maybe early fall anyway so maybe necessary to take them just at those times.