Quote:
Originally Posted by Astrofriend
I really like this lens. When I look at the oversaturated stars, looks if something is in the way for the light beam, like an aperture. Have to look into the lens and inspect it carefully.
/Lars
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Hi Lars,
Yes I think the lens is doing a good job except for some of the star shapes. You are right to suspect the lens aperture blades are a cause, suggested by the 8 points / diffraction spikes on the larger stars and possibly some slight distortion, possibly present as imperceptible spikes(?) on smaller stars.
As a test, you could try to use an external iris, maybe at 80-90% of the front element diameter, to see to what extent this mitigates the issue. If it does then you could possibly put up with using that permanently and loose 20% of the available light or you could consider lens surgery to remove the aperture mechanism. Have a good look inside the lens with a torch from both ends.
Good luck
Best
JA