Colour shift question

[Cloudwatcher]

I recently took a few E/P projection single frame shots of Saturn with the EOS350D

through a WO 15mm attached to the 5" Mak with the idea of trying to recording a

visual observers view.

Mixed results as expected but I also noted that some frames showed a shift to

blue on the left and to red on the right. Could this be a focus,lens or camera problem

or would the indifferent viewing conditions be to blame? Perhaps all four?

[daz]

Chromatic aberration is the term for this. Its where the optics cannot focus all the different lightwaves at the same point.

Was the camera directly coupled to the scope, or was they afocal shots? If the latter, then its probably the camera lens.

[FLO]

Blue on one side and Red on the other is normally caused by atmospheric prismatic distortion, from by the object being low down so viewed through more atmosphere. Happens a lot with Jupiter.

[GordonCopestake]

Chromatic Aberration can be caused by a multitude of things. Your MAK by it's nature wont introduce (much) CA to the image train, but the eyepiece you used could as could any other lenses in the system. Also the atmosphere itself can introduce CA in the right (wrong?) circumstances, this is most likely the cause. Best thing would be to try prime focus and see if it's still there, that rules out the eyepiece being duff. Not much else you can do about the rest though, other than wait for conditions to improve or change your equipment. Processing can remove some of the colour from your images, but not all

[GordonCopestake]

Beat me too it Steve

[Cloudwatcher]

They were eyepiece projection shots. The eyepiece was held in the adaptor and secured

at the scope end by the thread supplied and to the camera via the 'T' ring.

[Cloudwatcher]

Ooops! Overtaken by replies!

Thanks Guys. Had a feeling the viewing conditions might be the problem

as the colours do not appear in all the shots.

Actually, I quite like the effect in a schizophrenic sought of way! 8)