2-Minute Tutorial: A Simple Use of SubframeSelector to Prescreen Subs!

[@ABCMO-bl5pi]

This is exactly the kind of “how to” video I need. I have subscribed.

[@cosgrovescosmos]

So glad you find these videos helpful!

me too!

[@Skyguy055]

I have enjoyed all your tutorials and have quickly understood them without going on and on! The “Two Minutes” is a very good approach! Thanks for doing this, it’s very much appreciated.

[@cosgrovescosmos]

Thank you, Gregg - it's wonderful to get such feedback! Very much appreciated! All the best, Pat

[@jims9982]

Great video. My first time using Subframe selector is right now as I watch this video. I've had PI for about 4 months now. So much to learn.

[@cosgrovescosmos]

Glad it helped! Learning PI is a long journey but a rewarding one! Good luck with your efforts!

[@4auswanderer]

Amazing video. Thank you very much :-)

[@cosgrovescosmos]

You are welcome! Glad you found it helpful!

[@rvoykin]

Great video thank you!

[@cosgrovescosmos]

Glad you liked it!

[@AstroWorldTV]

Great! Vid!!! Thanks!

[@cosgrovescosmos]

Glad you liked it!

[@Mr77pro]

After calibrating frames you don't have to register and stack "manually " You can put calibrated frames back in WBPP without any calibration frames, and just check weighting, local normalization, registration and integration in the pipeline. As long as there are no calibration frames present it won't try to re-calibrate the frames. Also remember that if you're shooting OSC and you debayer as part of calibrating, you need to treat them as mono if you load them back into WBPP for integration.

[@cosgrovescosmos]

Good tip! Thanks!

[@theastrobistro9814]

Given rejection algorithms and weighting during integration, I’m wondering how much of a difference culling frames makes. I’ve done some rudimentary testing and found that keeping subpar frames didn’t appreciably affect the image quality but did help overall SNR. I plan to do some more in depth testing on this but I’m curious what your thoughts are.

[@cosgrovescosmos]

Integration and rejection algorithms do a great job in general. When I am dealing with Nebulae, then SNR is what I am going after, and the current weighting schemes (which are all some form of SNR) and rejection are just fine. When it comes to nebulae, I tend to shoot narrowband 5-minute subs. I never have as many as I would like, and I really hate the notion of culling those 5-minute subs that I have too few of to start with. So when I cull, few are cut, and the impact is not large. BUT - I find this to be different when we come to galaxy season. Here I want to maximize as much fine detail as I can. I'm also shooting 90-second LRGB subs. So I have a lot more subs, and during the spring, my seeing can be quite variable. I have found that culling images that have poor sharpness seem to make a difference in my images. With more subs, I can tolerate culling the worst ones, and I can take out enough to have an impact. I tend to use FWHM and ECCENTRICITY as the factors that drive the cull. The images that remain are much sharper and taken under better atmospheric conditions. Integration with these superior frames seems to yield a better result for me. Your mileage may vary. I started doing this for my Galaxy shots this past year, and I was surprised at the detail I can now see. I have not yet really seen the benefit for my narrowband nebulae shots. Here I tend to cull the worst images - usually only a few - this does not make a huge difference, but I feel better doing it. Thanks, Pat

[@theastrobistro9814]

@@cosgrovescosmos Thanks for the detailed reply. I hadn't thought that it may make a difference whether the target is a nebula or a galaxy. My test was done on Ha nebula data. I am currently working on a project covering M81 and the surrounding region. I'm shooting (no pun intended) for 30-40 hours total integration combining HaLRGB so I should have plenty of data to do some more culling tests. Clear skies!

[@patrickcosgrove2944]

@@theastrobistro9814 30-40 hours on that target would create an amazing image! With my tree lines - I can't get more that about 3 hours a night on a single target, and 30-40 hours is unlikely with our weather. Good luck with this project!

[@theastrobistro9814]

@@patrickcosgrove2944 I'm fortunate in terms of sky clearance on my property. Weather, however, is another story. I got no imaging done between 12/31/22 and 04/02/23 due to weather. It takes me a long time to complete a project, but I enjoy going deep on a target. I love to see details in a final stack that are invisible in a single sub. It satisfies the explorer in me!!