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Chromatic Abberation, Collimation or Filter Issue?

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#1 BlakPhoenix

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Posted 06 June 2020 - 10:03 PM

Hi all,

 

I have the 190mm Maksutov Newt and am seeing an annoying issue with my stars where my stars have orange/blue fringing on them.

 

star colours.PNG

 

I can't work out what's causing this issue and would love your thoughts on it. I hope to be able to rule out the filter the next time I have clear skies, but my stars seem round which makes me think it's not a collimation issue? This screenshot is taken from the centre of the frame and I wouldn't think I would have traversal aberration that close to the centre point.

 

Full image train:

SkyWatcher 190mm MakNewt

Moonlite CR2 Focuser

IDAS LPS D2 filter

ASI294MC Pro



#2 Rickster

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Posted 06 June 2020 - 10:25 PM

Looks like atmospheric dispersion to me as well.  Does the aberration go away for objects that are high in the sky?


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#3 Jon Isaacs

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Posted 06 June 2020 - 10:27 PM

Looks like atmospheric dispersion to me as well.  Does the aberration go away for objects that are high in the sky?

 

:waytogo:

 

You beat to it. It looks like atmospheric dispersion to me.

 

Jon



#4 BlakPhoenix

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Posted 06 June 2020 - 10:33 PM

Looks like atmospheric dispersion to me as well.  Does the aberration go away for objects that are high in the sky?

Oh I didn't even think of that! I think you may be right, here's an image from earlier in the night where the object was higher overhead and the effect seems less pronounced:

 

star colours2.PNG

 

That's almost more frustrating as I can't fix it! Haha.


Edited by BlakPhoenix, 06 June 2020 - 10:34 PM.

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#5 BlakPhoenix

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Posted 06 June 2020 - 10:57 PM

For anyone else coming across this issue some good reading can be found here: http://www.astropix....dispersion.html

 

This effect can also be helped in post by re-aligning the RGB colour spaces.




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