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Need help what this is


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I took a few pics with my sigma 70-200 f/2.8 at 200mm ( 5 min single pic ) around Vega and i got this green looking nebula that i dont know what it is ??

Need help :-)

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Hi, i can't tell for sure the orientation of this shot but it may be coma produced by Hip 92791 & Hip 92728 (no laughing please), i am just comparing your shot with Stellarium.

You have a similar strange pattern around all your stars in the shot so there is definitely something optical going on there.

Like Freddie most of the stars have this artifact, i have something similar, more prominent on larger stars, if i use my f1.8 wide open so i have to stop it down & mine looks like coma, that's my best guess sorry if i am way off though.

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It isn't just related to the bright star as you can clearly see a similar pattern around the stars in your M101 shot. Don't know exactly what is causing it, but you have some kind of optical issue there with all your shots.

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If the very first image you posted is full frame then it looks like internal reflections. Look where the centre of the image is then see how the bright star and flare are equally spaced either side.

This would naturally lead you to assume that if you moved the star slightly further away from centre the flare would also move away from centre. This is not always the case. A zoom lens has an awful lot of reflective surfaces that send light all over the place. The same may also not follow if you moved the star closer to the centre.

Just be aware where you're pointing when a bright star is in frame. The other one to watch is if a bright star is just out of frame where you can end up with flaring right across the image.

This leads straight into the genius of Fraunhofer. He designed a prescription where neither of the front lenses reflected off each other and then down the tube to the eyepiece.


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The first is full frame yes, and yes i can see what you mean it mirrors over to the same spot on the other half.

maybe its something to do with the Roxcore UV-filter i have on the lens ??

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