Calibrated Ha Doesn...
 
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2022-09-02: APP 2.0.0-beta4 has been released !

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Calibrated Ha Doesn't Look Correct - Too White in Middle


(@jhunt703)
Hydrogen Atom Customer
Joined: 9 months ago
Posts: 2
Topic starter  

 

 

Hello,

New user here

and was hoping I could get a bit of help with a problem.  I've taken mono L, Ha, R,G,B images with the 1600mm Pro and have used APP to calibrate each channel.  The calibrated LRGB lights look good, but the calibrated Ha lights seem to bright in the middle - They don't look correct.  My details are as follows:

L - Using 50 Gain, 10 offset and Exposure of 45sec. Darks at 240 sec. @ 50 Gain. Flats & DarkFlats of 50 Gain @ same exposure times using NINA's FlatsWizard.

RGB - Using 50 Gain, 10 offset, and exposure of 60 sec. Darks at 60 sec. @ 50 Gain. Flats & DarkFlats of 50 Gain @ same exposure times using NINA's FlatsWizard.

Ha - Using 139 Gain, 10 offset, and exposure of 240 sec. Darks at 240 sec. @ 139 Gain. Flats & DarkFlats of 139 Gain @ same exposure times using NINA's FlatsWizard.

I was thinking it was related to the flats or dark flats, but when I calibrate the Ha frames using only lights and darks I still get the same issue of a brighter area in the center of the calibrated lights.

Attached are images of the lights (linear) and Lights (Calibrated).  You can see the brightening of the image center in the calibrated frame. Also included images of my D, DF, F, MDF, and MF for reference.  

MF HA 139 GAIN
MDF HA 139GAIN
F HA 139 GAIN
DF HA 139 GAIN

 

L (Linear) HA 139 GAIN
L (Calibrated) HA 139 GAIN

 

Not sure what I'm doing wrong, I'm very new to this.  Going a bit crazy here : )

Thanks,

Joe 


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(@vincent-mod)
Universe Admin
Joined: 5 years ago
Posts: 5001
 

Looks to me as if you have variations in your flats regarding what you're seeing, is that correct? You'd want a flat to be very similar, the same, across the panels as they need to capture the true vignetting profile and any possible dust. Now when not using them and still getting this brighter spot, could you also take out the darks and any other calibration data to test that as well?


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(@jhunt703)
Hydrogen Atom Customer
Joined: 9 months ago
Posts: 2
Topic starter  

@vincent-mod Without the Flats and Darks I don't see the bright spot in the lights alone.  Do you think the problem is in the original flats?  I could take a new set of flats and check.  


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(@vincent-mod)
Universe Admin
Joined: 5 years ago
Posts: 5001
 

Well you mentioned it was still there with the darks added, so removing those has solved the issue? That could point to an issue with the darks in this case.


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