Quote:
Originally Posted by Tandum
I thought I'd finish this off instead of starting another thread.
What we found was one leg of the spider had been stretched by 2mm. To offset this I added packing to the other leg to center it in the tube. However, this introduced enough slack in the spider to allow it to twist and this twist changed depending on the altitude and because the secondary was so heavy the twisting then distorted the tube which gave us crazy results.
Peter got a new spider for the newt. Straight away it collminated at elevation and started to work however there is still a flex problem. I stuffed a camera with an OAG down it's throat and the flex issue was gone so it was external. I then removed the guide scope from the top of the newt and put it on a SBS bar with a tak fs60 as a guider and still saw intermittent flex even at 120sec subs. I tried wrapping a strap around the tube and the guider and this reduced flex a lot but it is still there. I think those GSO rings with the single mounting bolts are just not good enough for big newts.
Here's a couple of snaps under a bright moon.
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The Eta Carina shot seems pretty sharp. I can't see any elongated stars in it. The Omega Cent however is different - there does seem to be an elongation in the horizontal - or is it my astigmatism?
Peter