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Old 18-10-2018, 02:38 PM
gb44 (Glenn)
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gb44 is offline
 
Join Date: Jul 2012
Location: Gold Coast
Posts: 273
Hey Bob

Astigmatism is clearly there when you look at the difference between 1 & 7 and between 2 & 8 out of focus images. There is the 90 degree difference in the light pattern.

The star field shows a uniform star shape distortion. If it aint tracking error then maybe some tilt in the focusser / imaging train.
I have seen this star shape when using the old Meade DSI and I attributed it to oblong pixels! ZWO say their pixels are 2.9 x 2.9micron so that shouldnt be the cause - anyone else seeing this with the same camera?

miscollimation could cause that flared focussed star image. Final collimation visually at high mags should help there

No sign of coma there IMO.

Cheers
GlennB
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