I admit to relying too much on software tools to grade subs prior to processing. Whether it is DSS, SGP Image Grader, etc they seem to fall down in the area of good star shape culling. I have recently gone back to opening every captured sub with SGP enlarged stretched view before i process them to avoid 'contamination' of the stack. This becomes very labour intensive when trying to cull all the 'fast' subs that the ASI1600 can produce. My vision problems are now making this a more difficult task, even with a large editing screen. I am reduced to trying to analyse star shapes with just my good left eye, as macular degeneration induced distortion in the right eye makes it the only option; this is putting a strain on my remaing good eye that i would like to protect.
Can anyone recommend a 'tool' that can be used to validate star shapes, and not just count stars and produce a histogram value. Please no PI solutions.
I see that Billdan had a similiar question earlier this year and respondances seemed to rely on an eyeball cull. The eyeball cull is getting too difficult with my macular distortion, hence the revisit.
Thanks Colin, i have found a thread on CN from 2015 that discusses this topic. It looks like in CCD Inspector, Aspect Ratio is a measure of roundness. I need to know if that can be run as a batch process against a file of subs. I want to continue to use SGP for everything i can.
With CCDInspector you can load an entire folder of subs in, push measure all and it'll calculate the Aspect (roundness), contrast and background level. You can use to to calculate sensor alignment and collimation as well.
agree with Dunk, PI is good for this - it would maybe even make sense to get PI and only use it to select your best subs, if it helps protect your seeing and increases your enjoyment of the hobby.
The Stack dialog in MaxIm also does this (analyze all imported subs and rank according to FWHM, Aspect ratio, brightness etc...) It is very easy to use even without reading the manual. It operates on files (it does not load the images into memory) hence you can stack unlimited number of large subs.
What I do is specify the subs on disk to use (it puts them into LRGB branches), set the criteria threshold, run the automatic measure which then marks all the bad frames with an red x in the list. Then I inspect the ones around the good/bad divided line, to maybe change the threshold or manually cull the ones it didn't catch. Using the arrows keys to move up down the list updates the preview window to give visual feedback. The online helps explain it a lot better than I can.
Thanks for the advice below. Looking at it from a cost perspective, and considering all i want from the tool is star shape information, then CCD Inspector is the best choice. It is $100 cheaper than the lowest cost alternative, and actually has some other features i might use.
