Hot and Cold Column...
 
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Hot and Cold Column Problem  

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(@detoxx)
White Dwarf Customer
Joined: 3 years ago
Posts: 22
February 27, 2020 21:52  

Hi Mabula,

its me, again :P.

I have a little Problem. I book a few Sessions with the Chilescope. Hell, that are damn good Pictures, but the Sensor itself and the Calibration is very hard to get. There are many Stripes and Columns, Bad Pixel etc.

So i give the Calibration a try - more then once. But i have a Problem with these Stripes - see the Picture.

test

On the left Side is the uncalibrated Lightframe, on the right side the calibrated one. Im using Cold Column 9 and Hot Column 9. The Black Line is gone, the white Line is still there, but on the right side from the white line, is a blurry line. But on the Lightframe, there is no line to remove.

Thats on OIII and HA. I dont manage to remove this Line without blurry the other Area.

Please Help 🙁

Greetings, Markus

This topic was modified 2 years ago by Detoxx

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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
February 28, 2020 14:29  

Dear Markus @detoxx,

Before performing cosmetic correction, it's preferred and much better to make sure that the data is calibrated with a matching masterdark, a Masterflat and a Bad Pixel Map. Have you done this?

If you apply a Bad Pixel Map, it will always be better than a cosmetic hot pixel correction.

A matching MasterDark should really help with correcting bad columns, any remaining visible bad columns then can be corrected cosmetically.

Do you have calibration data, like masters for your raw frames?

kappa 9 for the columns is very low... that will usually not correct everything, best to use a value between 5-8. The lower the kappa, the more will be corrected, so be carefull, if you set it too low, too much will be corrected.

Cheers,

Mabula

 


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(@detoxx)
White Dwarf Customer
Joined: 3 years ago
Posts: 22
February 29, 2020 19:14  

@mabula-admin

Hi Mabula. Yeah i know, i always use a BadPixelMap for all Sensors. But on Chilescope, the Sensor have huge Problems with these Lines. And these Lines are not Corrected with the Darks or Bias. I do this several Times. 

I remove the Lines manually in Photoshop, not a big deal, but it takes Time. 

Thanks for your reply!


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(@vincent-mod)
Universe Admin
Joined: 4 years ago
Posts: 3694
February 29, 2020 23:05  

If they are not corrected at all with the darks, it might be that the calibration data is not right somehow. I would also ask the manager of the telescope in that regard.


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