7 replies to this topic

[KTAZ]

Hello all;

 

I have my remote observatory up and running and have found that the identification of high clouds in subs is not as easy as it was in a light polluted environment. At my home location (B6) clouds can easily be seen by Blinking my subs...if I get white gradients in the frame...clouds. Easy peezy.

 

At the obsy (B1) clouds have no ground effect light to reflect back...they are literally black. So seeing them in subs to cull them out is a bit more difficult.

 

What techniques (aside from Blink) do some of you remote site APr's use to identify and cull subs that have high, thin clouds?

[Michael Covington]

I think the general idea is that software uses the star count as a criterion.

[Midnight Dan]

PixInsight's Subframe Selector process provides a wide variety of metrics on your subs.  The graphs show the change over time.

 

The star count graph should give you a good idea of when the clouds were causing problems.  SNR should help too.

 

-Dan

[jml79]

SkyStory did a great video on SubFrame selector and he has very dark skies too. I use his 4 criteria and have noticed a solid improvement in my stacks vs just using blink.

 

https://www.youtube.com/@SKYST0RY

[smiller]

Lots of good suggestions already.  One more:  I use NINA and I have the number of stars (along with HFR and other capture stats)  recorded in the file name which makes it very easy to identify the images with low star counts (or poor HFRs) just by the file names.

[sn2006gy]

NINA also has a great plugin "Session Metadata" that will dump the metadata.csv into your imaging folder with the following data:

 

ExposureNumber,FilePath,FilterName,ExposureStart,Duration,Binning,CameraTemp,CameraTargetTemp,Gain,Offset,ADUStDev,ADUMean,ADUMedian,ADUMin,ADUMax,DetectedStars,HFR,HFRStDev,FWHM,Eccentricity,GuidingRMS,GuidingRMSArcSec,GuidingRMSRA,GuidingRMSRAArcSec,GuidingRMSDEC,GuidingRMSDECArcSec,FocuserPosition,FocuserTemp,RotatorPosition,PierSide,Airmass,ExposureStartUTC,MountRA,MountDec
217,D:/Imaging/Barnard's Loop - Horsehead/2024-11-26/LIGHT/2024-11-26_23-37-52_L_-10.10_120.00s_0217.fits,L,2024-11-26 23:37,120,1x1,-10.1,-10,100,50,720.5926,1147.0938,1111,706,65535,3071,1.7484,0.1631,10.076543576457915,0.4255764350999695,0.1002,0.5513,0.0804,0.4423,0.0598,0.329,34965,21.23,179.2897,West,1.4233,2024-11-27T05:37:52.1855321Z,85.84385354568914,-1.4741889465746498

[KTAZ]

Great suggestions. I have already implemented the star counts into my file name, but I also plan to play with the Session Metadata plugin this weekend.

[jml79]

Great suggestions. I have already implemented the star counts into my file name, but I also plan to play with the Session Metadata plugin this weekend.

I like adding the FWHM to the filename. I believe you have to have Hocus Focus installed to do this but who doesn't use Hocus Focus. Anytime it can't determine a FWHM due to clouds etc it puts NaN in the filename and that lets me delete all of those nasty subs in seconds with a quick command line or file search.