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Why are my flats not working?

DSLR Astrophotography
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#1 HSkaane

HSkaane

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Posted 15 January 2022 - 05:40 AM

I have usually had quite a lot of success with flat frames however after i have added i fieldflattener to my setup it seems like they have limited effect in DSS

 

My method is two layers of white t-shirt with an ipad screen shining white light and shooting in Av mode on my Canon 550d making sure the exposures are all the same length

 

Here is my autostretched (in Siril) masterflat, it seems quite faint in my opinion:

MasterFlat
 
Here is the histogram of one of the flat frames (1" exposures each):
Histogram

 

And here are two of the images i get from the flats in DSS:

C34
Horsehead
 
Images were processed with autostretch, colour calibration and background extraction in Siril

 

Thanks.


Edited by HSkaane, 15 January 2022 - 05:42 AM.


#2 michael8554

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Posted 15 January 2022 - 06:57 AM

Your Flats look fine.

 

IMO the artefacts in your two images are due to reflections from bright stars, which Flats won't be able to correct.

 

And I'd guess that the Horsehead images are from sets of Lights with significant rotational difference ?



#3 HSkaane

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Posted 15 January 2022 - 07:22 AM

Your Flats look fine.

 

IMO the artefacts in your two images are due to reflections from bright stars, which Flats won't be able to correct.

 

And I'd guess that the Horsehead images are from sets of Lights with significant rotational difference ?

Both the images have the same camera position just the Horsehead had been flipped in processing

 

Is there anyway to reduce the reflection?

 

Also why is the reflection in the Horsehead dark whilst in the Veil it is light?


Edited by HSkaane, 15 January 2022 - 07:36 AM.



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