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GUS

Spherical aberration in achromats anyone?

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Hi,

Has anyone noticed any spherical aberration or off axis aberrations (field curvature, astigmatism & coma) in an achromat in h-alpha? Or a better overall image quality in any way (clarity, resolution, sharpness, contrast, brightness etc) using an APO or ED over an achromat? Thanks

 

Edited by GUS

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The only aberration which can/ could be an issue would be spherical aberration.

Although the achromatic may be well focused for Ha there is a possibility that SA may not be well corrected.

This has been the subject of much discussion over on the solarchat forum, and there is a vendor who sells an SA corrector......

Based on my own experiences with Coronado Ha filters and numerous PST mods I haven't found any significant issues using telescopes like the SW ED80 or the TS102.

Others may comment on their experience.

 

Note that the Lunt Ha scopes only have a singlet lens objective, and this works very well.

 

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Thanks Merlin 66, 

I was asking since I use my Quark Chromosphere (anyone out there with the Prominence? Worth it?) on a sv60eds but plan on getting the Orion short tube 80 which is no APO. Maybe as much if not more attention should be placed on the ep that will likely have as much a say in the image that will finally hit you in the back of the eye.

The lunts having a single lens definitely says something.

Edited by GUS

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