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31 July 2020 - Comet Registration video tutorial using APP 1.083-beta1 released.

30 July 2020 - APP 1.083-beta1 has been released introducing Comet processing! This 1st beta has comet registration. The stable release will also include special comet integration modes.

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Newby Question on Satalite in Light Frames  

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(@j1will)
Hydrogen Atom Customer
Joined: 3 months ago
Posts: 2
August 20, 2020 23:50  

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)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 6
August 22, 2020 02:53  

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)
Brown Dwarf Customer
Joined: 2 years ago
Posts: 6
August 22, 2020 03:04  

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!


(@vincent-mod)
Quasar Admin
Joined: 3 years ago
Posts: 2453
August 22, 2020 16:31  

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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