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Posted by Gavin Blakeman on March 31, 2002 05:46:13 UTC

Thanks Bob,

I had another look last night. Looked at Sirius through both eyepieces. The astigmatism is gone. (Colluminaiton) On stars I can get the shorter ep to focus to a pinpoint.

When i defocus the image, (forward or backward) the image is now round.

I do wear glasses because of astigmatism.

Have also tested the mirror using foucalt test. However have only done qualitative and not quantitative test. There is a central pit visible in the mirror, but am not concerned as the pit will be covered by the secondary. (F8 8" is just outside of spherical, have parabolised mirror but cannot make quantitative foucalt test work for me)

My plan forward is to get another ep (7.5mm) and a 2×barlow and do some further testing on the mirror before coating.

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