Quote:
Originally Posted by Shiraz
yep, looks like that is the problem - no offset and your input light is glancing by one side of the OTA edge, producing a lopsided diffraction pattern.
You can't get the light column centered without putting in a secondary offset.
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Ray, I see the results differently:
1- Yes, I agree that the secondary mirror is not mounted with away-from-focuser offset. This is obvious based on the fact the spider vanes reflection is centered against the secondary mirror silhouette
2- Because the secondary mirror was not mounted with away-from-focuser offset, it is expected that optical axis of the primary mirror to be tilted towards the focuser. This is obvious in the photo of post # 10. The flash photo reaffirmed what I can see in post # 10 photo.
3- The tilting of the optical axis towards the focuser will not cause any lopsided diffraction pattern as you have suggested
I do not see any issues in the photos uploaded by the OP. I do see the spider vanes clips in the light path but I doubt this is the reason. The OP stated that one side of the inner wall of this focuser was visible via the secondary->primary->secondary reflection. I examined that photo but it was unclear to me if this was the case.
Ray, you had to apply the away-from-focuser offset because you stated that your OTA opening is too tight which means tilting the primary mirror towards the focuser will cause the OTA edge get in the light path. I do not see it in the OP's case.
My setup is similar to the OP's though I use my scope for only visual.
Jason