Great video - very straightfoward - You would think that FWHM and Stars number subfrane selection, could easily be added as a setting in WBPP (after calibration).
thanks for this. i admit to being worse than cuiv as i am super-lazy. i use dss [deep sky stacker, freeware] to "grade" my images under register which sorts them by "score". I believe the score is determined by star roundness and size [not well described]. HOWEVER< it effectively shows me quickly which images are super-bad. then while in DSS I delete those images from my hard drive. I then go to PI and place into blink, review them to reassure myself, then place into WBPP. I love PI but the inability to quickly delete super-bad frames is a bit disappointing,unless I am missing something. love your content, btw.
Thanks Sascha. I agree that SS is an essential process to weed our bad frames that other processes like WBPP won’t see. Nice demonstration. I also add these cross checks to my routine … Stars can also detect the odd frame when there has been a “stutter” in the the guiding producing double stars. Sometimes I miss these in blink. Checking for overly eccentric stars. Checking for excessively high medians with high SNR - these are usually great quality pics of faint high level clouds😊. Creating a weighted score for the best blend of FWHM and eccentricity-from this I select my reference frame for registration. I figure that the tightest and roundest stars make for the best registration reference. I then also note the best PSF signal ratio frame to use as the reference frame for stacking-I like the NSG script for this especially when stacking multiple nights In gradient skies, which is is mostly the case. I also find the SS discipline often provides interesting and Beneficial insights to take back to the night skies. Best, Gordon PS. Many disagree with me and simply stick everything into WBPP.
Great input Gordon, thanks! I completely agree with you that dubbing anything just into WBPP is suboptimal and I think I can also show why in this video. But where you perhaps should reconsider your strategy is with the eccentricity.... After my Blink video I had the honour of getting feedback from Adam Block. He mentioned that egg shaped stars should not be removed, as WBPP will correct that (assuming the majority of the pictures has round stars). Based on that, the egg-shaped stars will do no harm but your S/N ratio will benefit from leaving them included.
Hi Sascha, If you use the Sigma term for the values you dont have to guess. The light gray margins are +2 & -2 Sigma, the dark gray margins are +1 & -1 Sigma and the black line in the middle is 0 Sigma. As an example of the approval i use that also includes the weighting used by WBPP, please see below. StarsSigma > -2 && FWHMSigma < 2 && PSFSNRSigma < 2 && PSFSignalWeightSigma < 2 I hope this is helpful. Cheers, Canov
Quick question, when I update the functions to remove certain parameters the red X appears on the graph window but not on the subselection window. Then when I output the files all files are output regardless of the red X in the graph window. How do I get the rejects to show rejected in the subselection window?
I tend to diseagree with you about not calibrating before using SS since it tend to pick most hot pixel as stars and screw some important data like Eccentricity.
a) As hot pixels are equal throughout all pics to stack they will not influence the eccentricity delta in-between the pics b) Eccentricity should not be an elimination criteria according to Adam Block as it is levelled out throughout stacking c) Thanks to BlurXTerminator Eccentricity is not an issue at all anymore - guess yourself if I'm joking or not... ;-) d) Even if you could prove me wrong with a, b, and c - I would still not interrupt my stacking process - there are certain things which deviate too much from the effort I'm willing to dedicate to processing.... ;-)
Very helpful. Thank you so much!
Great video - very straightfoward - You would think that FWHM and Stars number subfrane selection, could easily be added as a setting in WBPP (after calibration).
thanks for this. i admit to being worse than cuiv as i am super-lazy. i use dss [deep sky stacker, freeware] to "grade" my images under register which sorts them by "score". I believe the score is determined by star roundness and size [not well described]. HOWEVER< it effectively shows me quickly which images are super-bad. then while in DSS I delete those images from my hard drive. I then go to PI and place into blink, review them to reassure myself, then place into WBPP. I love PI but the inability to quickly delete super-bad frames is a bit disappointing,unless I am missing something. love your content, btw.
Thanks Sascha.
I agree that SS is an essential process to weed our bad frames that other processes like WBPP won’t see. Nice demonstration.
I also add these cross checks to my routine …
Stars can also detect the odd frame when there has been a “stutter” in the the guiding producing double stars. Sometimes I miss these in blink.
Checking for overly eccentric stars.
Checking for excessively high medians with high SNR - these are usually great quality pics of faint high level clouds😊.
Creating a weighted score for the best blend of FWHM and eccentricity-from this I select my reference frame for registration. I figure that the tightest and roundest stars make for the best registration reference.
I then also note the best PSF signal ratio frame to use as the reference frame for stacking-I like the NSG script for this especially when stacking multiple nights In gradient skies, which is is mostly the case.
I also find the SS discipline often provides interesting and Beneficial insights to take back to the night skies.
Best, Gordon
PS. Many disagree with me and simply stick everything into WBPP.
Great input Gordon, thanks! I completely agree with you that dubbing anything just into WBPP is suboptimal and I think I can also show why in this video. But where you perhaps should reconsider your strategy is with the eccentricity.... After my Blink video I had the honour of getting feedback from Adam Block. He mentioned that egg shaped stars should not be removed, as WBPP will correct that (assuming the majority of the pictures has round stars). Based on that, the egg-shaped stars will do no harm but your S/N ratio will benefit from leaving them included.
Excellent feedback, and a good tip. I will use that. Thank you.
Hi Sascha,
If you use the Sigma term for the values you dont have to guess.
The light gray margins are +2 & -2 Sigma, the dark gray margins are +1 & -1 Sigma and the black line in the middle is 0 Sigma.
As an example of the approval i use that also includes the weighting used by WBPP, please see below.
StarsSigma > -2 &&
FWHMSigma < 2 &&
PSFSNRSigma < 2 &&
PSFSignalWeightSigma < 2
I hope this is helpful.
Cheers,
Canov
Thanks - great input!!!!!
forgive my ignorance but is this a selection setting withing the WBBP? if so where can input these settings?
Great! Thank you.
hi Sasha, but is the subframe selector also included in wbpp?
Kind off, WBPP does the weighting of the pictures based on criteria which you could also analyze in the Subframe Selector.
Quick question, when I update the functions to remove certain parameters the red X appears on the graph window but not on the subselection window. Then when I output the files all files are output regardless of the red X in the graph window. How do I get the rejects to show rejected in the subselection window?
I tend to diseagree with you about not calibrating before using SS since it tend to pick most hot pixel as stars and screw some important data like Eccentricity.
a) As hot pixels are equal throughout all pics to stack they will not influence the eccentricity delta in-between the pics
b) Eccentricity should not be an elimination criteria according to Adam Block as it is levelled out throughout stacking
c) Thanks to BlurXTerminator Eccentricity is not an issue at all anymore - guess yourself if I'm joking or not... ;-)
d) Even if you could prove me wrong with a, b, and c - I would still not interrupt my stacking process - there are certain things which deviate too much from the effort I'm willing to dedicate to processing.... ;-)