Select Your Best Subframes - Beginner Tutorial

[@WindyCityAstrophotography]

Thanks for watching, everyone! How selective are you with your subframes?

[@ClearAmbientSkies]

I felt a great disturbance in the Force, as if millions of subframes suddenly cried out in terror and were suddenly rejected. Great topic for a video. I learned something new! I'm already grading my subframes--for the first time beyond using Blink. Thank you.

[@WindyCityAstrophotography]

😂 yeah I feel bad for all those little subframes! Thanks very much, glad it was helpful!

[@SKYST0RY]

Hands down, the best video I've seen on the SFS.

[@amp2amp800]

Great, Nick! Thanks so much for this quick and clear treatment. Very helpful and refreshing.

[@gregerianne3880]

Great tool that I've never used (but will now), Nick! Thanks for another very helpful video.

[@deep_space_dave]

I did a search for Subframe Selector and your video came up :-). This is very useful as I am currently doing some lucky DSO imaging and need better star Eccentricity but don't want to manually blink through hundreds of images. Thanks for the video!

[@WindyCityAstrophotography]

Boom! Glad you found it, Dave!

[@josephluciani5531]

Brilliant! Much thanks Nick for a wonderful tutorial.😊

[@Lord_Whiteley]

A really great tutorial Nick ! As ever very clear and easy to follow and a lot more scientific than scrolling through “Blink” :)

[@WindyCityAstrophotography]

Thanks so much! Yes, more scientific for sure but I still love Blink! Just not for this work 😎

[@lesgatechair3907]

Enjoying your videos. Nice balance of needed details and clear directions and good example. Thanks from Tampa!

[@OutlandishJourneys]

Excellent explainer, Nick! Very helpful and will definitely incorporate this into my workflow...nice job! :)

[@WindyCityAstrophotography]

Thanks very much! Glad it is useful!

[@jeffreyvictor3678]

Once again...great video, great info!

[@TheNorthDevonOrganist]

Great and very informative and helpful video. Thank you so much!

[@georgesyrganidis2816]

Excellent tutorial mate!

[@astralbody]

I was wondering how this was done. Love these PixInsight from you. simple, make sense, and allow me to dive in without inundating me with excess info. thanks for another good video! Still working on my 16 pane mosaic, lots of work but looks good so far. Cheers! PS, I look through my frames and take out the obvious. In DSS I was more selective. I'll try this in PI!

[@WindyCityAstrophotography]

Thanks, Victoria! Glad you like the videos; it is a good challenge to limit video topics (and allows for more videos to be made!) so I am glad the format is useful!

[@robinwinsor4392]

Super helpful - thanks so much for posting this.

[@astrotimetraveller4622]

Nick, very useful. I use subframe selector, but haven’t used the expressions tab, which looks very useful, clear skies, Ian

[@WindyCityAstrophotography]

Glad it was helpful! Thanks, Ian!

[@astrophoto_andy3335]

I was hoping you'd get into the Expressions! Thank you! I'm a happy camper now.

[@WindyCityAstrophotography]

😁 thanks! Yes, they are super useful but not intuitive at first

[@JonnyBravo0311]

I use SFS and I get more and more selective as I acquire more data. For example, I might start off with FWHM < 6 and Eccentricity < 0.7... but tighten it up to FWHM < 4 and Eccentricity < 0.4 once I've got a few nights worth of data. Also, I put in my actual values. Easy enough to get from the FITS header. My process is basically use WBPP to do the calibration and weighting. Then bring the calibrated frames into SFS and determine what I want to keep. Then, I register the keepers and integrate them.

[@WindyCityAstrophotography]

Yeah that makes sense to get more selective with more data. I have done it both ways with WBPP calibration/weighting first or second and didn't see too much difference but definitely for multiple nights it might be the more efficient workflow to do it the way you describe. Thanks for sharing! 😎

[@JoesAstrophoto]

Great tutorial Nick, not sure I qualify as a beginner, but I learned some stuff! Thanks for sharing!

[@WindyCityAstrophotography]

Thanks, Joe! Haha yeah I was trying that word out for search engine reasons but this is something I didn't even think about as a beginner. Maybe expert beginners... 😆

[@markmuratore413]

Great video. Thanks very much for doing this!

[@WindyCityAstrophotography]

Thanks very much, glad you enjoyed it!

[@Zealor365]

Wow, great video...Learning how to improve my end result. Thanks!

[@WindyCityAstrophotography]

Thanks, Mark! Glad it was helpful!

[@arnsteindale5531]

Thanks for a really good and informative video. Thumbs up!!

[@WindyCityAstrophotography]

Thank you 😎

[@javiercuellolopez5610]

Great video !!. This method is before that I stacking, but Could I use the final frames in APP for stacking?. Thanks

[@WindyCityAstrophotography]

Yes, absolutely!

[@wallbke]

Super! Thank you.

[@WindyCityAstrophotography]

You are welcome, Kurt!

[@greenmjg7]

Thank you for this, made it easier to understand, and hopefully my images will be better by only using the best frames. clear sky's to you :)

[@WindyCityAstrophotography]

Excellent, thanks! So glad it was helpful!

[@greenmjg7]

@@WindyCityAstrophotography just ran my images from Monday through SubFrameSelector, an then opened one that not great and another that good, side by side can definitely see slight differences, thank you once again 👍🏼👍🏼😊

[@WindyCityAstrophotography]

@@greenmjg7 Nice! Glad to hear it! What was the target?

[@rodmanhouse]

what are the keystrokes for the boolan modifier you use to add ecentricty and median?

[@aluginbill6182]

Is that the ampersand symbol you’re putting after the values?

[@WindyCityAstrophotography]

Correct! Two of them.

[@simonpepper5053]

Hi Nick do you not use SNR weight as one of your parameters? Thanks

[@seriousbassface]

I'm still curious to see how picky you actually need to be as I just did a rough stack with lots of errors/clouds/ elongated stars. While it was not as sharp as I'm hoping for the stars were all round and it wasn't awful. I just captured 59 hours of data, I'm thinking of doing a stack with everything as is and then a very picky selection taking out the slightest errors to compare the two if I don't find a good answer to that before hand.

[@tomwall8403]

I'm just now getting to the point where I want to do this sort of thing. I'm using APP for my stacking. Do you, or anyone else, know of a way to sort and select subs by certain properties using APP? Thanks!

[@WindyCityAstrophotography]

That's a great question, but I will be perfectly honest I don't know APP. I have wanted to dive into it soon, so I may have an answer at some point

[@MrStacaz99]

What about subframe weighting? You really want to bump up the very best frames over the average frames that are accepted.

[@WindyCityAstrophotography]

Yes, I rely on the Weighted Batch PreProcessing script to take care of weighting my approved subframes. I could definitely do the weighting in Subframe Selector but it is so much easier to use the Nebula/Galaxy/Cluster weighting presets and then adjust the parameters from there vs manipulating the weighting equation. Gotta pick my battles for complication 😆

[@KopLamp]

I do a similar thing but then in Siril ;-)

[@WindyCityAstrophotography]

That works!

[@anata5127]

You need to put image scale there to get real numbers; not pixels, but arcsec.

[@kowalskik.1333]

ahm, didnt you forget the most important? Where is the side by side picture comparison? How can I know if this procedure makes a different?

[@stevendillon7049]

Nice. Do not get left behind > P R O M O S M!!!

[@JethroXP]

Nice presentation! The Subframe scale can be found by using Stellarium or Astronomy.tools and configuring in your camera and telescope, or using the formula Arcseconds/Pixel = (206.2648 * (Camera_Pixel_Size_in_μm) / (Telescope_Focal_Length_in_mm). And the Camera Gain can be found in the FITS headers of your Lights by opening one in PixInsight and selecting "FITS Header" from the "File" menu.

[@WindyCityAstrophotography]

Thanks, Jason! At some point I'll do a video on this process for configuring it for actual values rather than relative. I had configured it on previous computer at one point but hadn't gotten to it on the new rig 😆