Newby Question on S...
 
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Newby Question on Satalite in Light Frames


(@j1will)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 4
Topic starter  

I'm getting Satallites across light frames from time to time. Should I be eliminating those frames from the Light files list before processing them, or does the Satallite line get eliminated during the integration or calibration process?  Here is an example of a fits file with a Satallite line going across it attached.

 


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(@rhalbers3)
Molecular Cloud Customer
Joined: 4 years ago
Posts: 6
 

It depends upon the algorithm you are using during integration.  If you use a simple "average" stacking mode for your lights, then the satellite track will leave some faint "residue" behind, so you should remove that light frame.  If, however, you are using some form of Kappa-Sigma clipping for your stacking mode (recommended), then the pixels along the satellite track will be outliers and removed.  Any "residue" should be negligible or non-existent.  Run some experiments with both stacking modes and see for yourself.  🙂

Hope that helps.


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(@rhalbers3)
Molecular Cloud Customer
Joined: 4 years ago
Posts: 6
 

And APP should take care of this for you automatically in most cases.  Under tab 6) INTEGRATE, if you leave "integrate" set to "automatic" it will integrate your lights using either the "median" method (for less than 20 light frames) or the "average" method with "sigma rejection" (for 20+ light frames).  Both methods will remove the satellite track (but I suspect the "average" method using "sigma rejection" will be superior).  If you hover your mouse over the drop-down boxes in the INTEGRATE panel, you can get more help.  Again, experiment with the various options.  It's the best way to climb the learning curve.  Good luck!


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4727
 

In automatic mode, the "best" algorithm is chosen based on the amount of frames. But, if there is residue, you can try to set the algorithm yourself, like @rhalbers3 mentions, and lower the kappa values to get a stronger rejection.

Having more frames will also help with rejection.


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