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Old 20-11-2020, 07:49 PM
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xelasnave
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Checking subs.

How do you check your subs? I find what I am doing tedious..left click,open, enlarge ,inspect,next..I must have done 300 like that today and the failure rate..80%..demanding perfection if I am going to look at them before stacking..also how do you know if your dark is ok..I get subs with lines at the bottom which I throw out of course but how would you spot that in a dark....Perhaps has left me unhappy...there must be a better way.
So much for being perfect..not enough subs to stack..even did flats and dark flats...just disappointed nothing went well.
Alex
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Old 20-11-2020, 08:02 PM
Startrek (Martin)
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Alex,
I check the same way one by one using Astap
Slow but accurate , Iím not a rush anyway
If your imaging with short subs ( 30 to 60 sec) then your probably capturing in the hundreds, whereas most nights Iím only capturing 40 to 80 subs ranging between 90 sec to 300 sec
You can check your subs in DSS which might be quicker but you canít zoom in like I can with Astap, and Iím a fuss bum I like to zoom in and make sure even my tiny stars are round
Hopefully other folk chime in and offer suggestions or solutions
Martin
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Old 20-11-2020, 10:03 PM
glend (Glen)
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Alex, I always used FITS Image Grader, it is free from the SGP folks, and is a stand alone app.. It can work through a whole file of subs,. FITS Image Grader will calculate "whole-image" Half Flux Radius (HFR) in order to determine an image's relative focus (lower values are better), Number of Stars found and finally a proprietary "Score" that takes both HFR and Number of Stars into account to provide a single metric (higher is better).
You can read the whole description of what It does, here:

https://www.sequencegeneratorpro.com...-image-grader/

It will break your subs down by filter sub- group and provides a nice report. You can manipulate the files, Mark them, etc.
Great tool in my opinion.

It is a good first pass at checking, and can eliminate having to look at a number of bad subs manually. I do still examine subs manually but usually just a scattered sample, after the Image Grader did it's work. My attitude was that if Image Grader was showing a score that indicated good focus and maximum stars then the sub was pretty good already. Incidentally, the SD figure is the standard deviation of the HFR, which is a good way of knowing how far out any particular sub may be from the Mean of the file group.

Last edited by glend; 20-11-2020 at 10:18 PM.
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Old 21-11-2020, 10:23 AM
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xelasnave
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Hi Martin,
Thank you for your reply it seems we have a few things in common.
Hi Glen,
Thank you for your reply. I have been to the site, on my tablet, and will later download the software as it sounds the very thing I want.
Alex
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Old 23-11-2020, 06:24 AM
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The_bluester (Paul)
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I use the FITS image grader too, if I have lots of subs on a target it is a good way to quickly pick say the best 80% of them to integrate, ideally with enough left in the pot that I can use outlier rejection to eliminate satellite trails without any ill effects.
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Old 23-11-2020, 08:21 AM
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Merlin66 (Ken)
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Unable to download...
The SGP site seems to be unavailable
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Old 23-11-2020, 12:49 PM
Spidy (Phil)
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Quote:
Originally Posted by Merlin66 View Post
Unable to download...
The SGP site seems to be unavailable

I concur.
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Old 27-11-2020, 01:10 PM
Spidy (Phil)
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Tried again today, still unavailable.


Has anybody successfully downloaded this?
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Old 02-12-2020, 06:41 PM
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Gravity does not Suck

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I have not but they appear there via my tablet.
Talk about sub checking ..I have spent over yesterday and today about eight hours going thru subs of the Spider with a throw out rate of about 80% when I blew them up individually and asked does this one pass?...it is so hard throwing out subs but my new rule is if you have to think about keeping it well throw it out...anyways I still have maybe 500 subs left but this afternoon just stacked my greens and the new result was most pleasing..lots of little stars in the core area which in my last rendition showed nothing although the last image looked rather decent...anyways I plan to stack these final subs when I get plenty of power and a cool day...and even thinking to go thru again and be super critical and throw stuff out if it even hints at not being perfect...
The trouble is my subs are two different framings so I won't get a huge image but at least I will be able to tell if throwing out 80% was worth it...Alex
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Old 11-12-2020, 08:06 AM
RugbyRene (Rene)
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I use the Blink tool & Sub-Frame Selector in Pixinsight. I run Blink first to remove any really crappy subs then run SFS to weight my frames before integrating.
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