Long integration

[Pitch Black Skies]

How do I plan a long integration image?

Something in the region of 16-24 hours.

Do I calibrate my lights at the end of each night?

Do I then stack each calibrated night to produce my final image?

How do I ensure my framing is the same each night?

I'm using an ASIair Pro.

Thanks!

Edited December 22, 2021 by Pitch Black Skies

[vlaiv]

Calibration frames will depend on your setup.

If you have cooled camera (set point temperature) - you can take single set of darks - even after you've completed your imaging.

You can take single set of flats - if you keep everything the same between nights - meaning you don't take apart your scope and camera, but if you do - you'll need new set of flats for each evening. One set of flat darks should be ok - if you don't change exposure length (and you should not need to).

Flats are best taken after end of the session - just don't touch anything like focus or whatever. Focus needs to be as it was during imaging (focused on infinity).

As far as orientation goes - you can plate solve to get exact orientation of your framing, but I prefer to orient in either portrait or landscape (with respect to RA/DEC).

Even if you don't plate solve (which will give you angle - in above portrait / landscape case it will be 0° or 90°) - there is a trick to easily orient your sensor in wanted direction. Find bright star, center it, start exposure, slew in RA, stop exposure. Look at the image - bright star should make a line / star trail. Is it horizontal (or vertical for portrait)? No - rotate camera, center star and repeat, if yes - you are done - RA is aligned with horizontal (or vertical).

After you have gathered all subs - calibrate each with its own set of calibration frames and then throw them all into stack for final image.

[Lee_P]

I take 16 to 24-hour images using an ASIAIR Plus. Using Plan mode you can plate solve to the same location over many nights. Don't remove your camera / rotate it during the project, and then your framing will be consistent.

As for calibration, are you using a cooled camera? That makes things a lot easier. Always take your subframes at the same temperature (e.g. -10 degrees C). You can then use one set of temperature-matched dark frames. As for Flats, one set taken at some point during your imaging project will do. You can then calibrate all your data together at once, rather than night by night.

More info here.

[Pitch Black Skies]

Awesome, thanks guys.

I'm using a cooled 533 @Lee_P.

So what got me interested in this is actually a very interesting project you were involved in here.

@vlaiv

[Lee_P]

15 hours ago, Pitch Black Skies said:

Awesome, thanks guys.

I'm using a cooled 533 @Lee_P.

So what got me interested in this is actually a very interesting project you were involved in here.

@vlaiv

I'm glad you found that article interesting, the fact that you've got a cooled camera makes things a lot simpler

[Pitch Black Skies]

2 hours ago, Lee_P said:

I'm glad you found that article interesting, the fact that you've got a cooled camera makes things a lot simpler

Crikey! It didn't dawn on me that you were the author. Great work Lee! And cool website btw 😀