Calibration Frames: How To Take Them & Why You Need Them

[@MrFaiGor]

more sharing is expected. Thanks.

[@astronomass]

Thanks for watching!

[@signupstuff]

Showing the 'why' we should take calibration frames was super-helpful. Every other video I've seen on the topic just talks to it but there's nothing like actually seeing it that drives home why it should be done. Thanks for taking the time. Also - you didn't say so explicitly but I was relieved to see a temp range at 3:54. A session could last hours and could start at one temp and end ~10 degrees cooler by the end of it. So with a DSLR I don't have to sweat over getting that one single temp for dark frames? It's invariably going to be on the colder end at the end of the session.

[@astronomass]

Thanks for taking the time to watch and comment! Dark frames with a DSLR aren't an exact science, don't worry too much about getting the temperature spot on. Having dark frames within 10 degrees or so is still much better than no dark frames at all. Make sure to take advantage of cloudy nights to add a few sets of dark frames to your library. Good luck and clear skies!

[@domwonders]

Thank you for your in depth explanation about the calibration frames, this helps a lot.

[@astronomass]

You're welcome, I'm glad you found it helpful!

[@markwright748]

Very clear presentation. Thank you

[@astronomass]

You're very welcome, thanks for watching!

[@DarkGhostAnubis]

Thank you for your simple explanation of these processes im new to astrophotography and this helps alot

[@OscillateDarkly]

Great vid, how do you deal with an auto focuser and flats?

[@astronomass]

Thanks for watching! Focus is important for flats, so I always take mine the morning after imaging. Small changes in focus throughout the night aren't a big deal, but make sure your focuser position doesn't reset to zero / home when your session is complete.

[@OscillateDarkly]

@astronomass cool cool. Thanks for getting back to me so quickly

[@benjamincasatimcintosh2918]

I would have liked a final stack comparison of no calibration and all the combinations of calibration frames. Very nice video

[@astronomass]

That's a really good idea, I wish I had included that! I'll keep that in mind for future image processing videos. Thanks for watching!

[@rickbattle5706]

Thank you, great info. Suggestion, see if you can improve the audio some. Otherwise, excellent.

[@astronomass]

Thanks for watching, and I appreciate the feedback!

[@huddless50]

Good job. Thanks. Do you have a link to the software you used?

[@astronomass]

Yup! I use DeepSkyStacker for stacking and ASI fits viewer for reviewing images. Next time I'll put them in the description. Thanks for watching! deepskystacker.free.fr/english/index.html astronomy-imaging-camera.com/software-drivers

[@leonardorser3455]

thankyou

[@paulwilson8367]

How long should it take your 2600MC to save a bias or a flat frame to your PC disc? I am doing this with a remoted rig. It is taking more than 1 minute to save each frame. That doesn't seem right? This makes taking sky flats quite difficult because the ambient light is changing quickly. This wasn't always happen and I don't know what to suspect as the cause. The Mele Quieter 3 Mini pc used to do this in half the time.

[@AstroBethTeal]

How is it that the frame is being subtracted if it is stacked with others?

[@astronomass]

Good question! I use the word "stack" pretty generally in this video, when in reality, it's stacking and calibration. The short answer to your question is the stacking software knows what to do with the calibration frames, usually some form of subtraction. The full process, at least in DSS, is something like this. 1. You upload all of your lights, darks, flats, bias 2. DSS stacks (average) your darks, flats, bias independently to create a master dark, master flat, master bias 3. DSS applies (subtraction) your master dark, master flat, master bias to every individual light frame 4. DSS stacks (average) all of your calibrated individual light frames to create the final stacked and calibrated image I hope this explanation helps, and thanks for watching!

[@AstroBethTeal]

@@astronomass Ohhh that makes sense. I’m new to AP so I try to ask about every term or any little thing I’m confused about. Love the video, I actually got a bit emotional watching it because I had been struggling to understand calibration frames for so long but this is the video that made it easiest to understand and helped me not give up. Thanks for sharing your knowledge.

[@astronomass]

Thank you for the kind words that means a lot! The early days of astrophotography are definitely the hardest, so many things to learn and frustrating moments along the way. Just keep pushing and you will create images that remind you why you started the hobby in the first place. Thanks for taking the time to watch and comment, clear skies!

[@crateer]

When using a DSLR, just check whether Dark frames are actually helping you. Dark frames often do not help to reduce noise. So for my DSLR, darks are pointless. So keep that in mind and check before "wasting" hours ;) Edit: obviously you need to dither to get rid of hot pixels etc. Also: Darks do not make my images worse, but they provide absolutely zero visual benefit to my images, other than lowering my SNR a tiny bit (which is expected).

[@astronomass]

This is a good point, I have heard of others saying their DSLRs did not benefit from dark frames. Definitely worth the trial and error to determine the situation for your specific camera. Thanks for sharing your experience and for watching the video!

[@chrisrose832]

all the calibration frames should be made in the same TEMPERATURE too