Help to diagnose fringing

[tobblerone]

Hello!

When I take pictures I get an uneven orange fringing (I think thats the term in english atleast) around bright objects including stars, planets and recently very noticable the moon. Can someone explain whats causing this?

Image for example, shot with a Canon 6D using a William Optics GTF81 and a 2,5 powermate. At the bottom you can see a distinct orange hue around the edge that disappears the further up you come.

Thanks in advance! /Tobias

[andrew s]

I don't know what elevation the moon was at but it could be atmospheric dispersion.

The highter the air mass the greater the effect.

Regards Andrew 

[tobblerone]

Thanks! That could explain it. It was between 25 and 30 degress above horizon. The planets that I photographed at that time was even lower so it makes sence. Will keep that in mind for the future.