Quote:
Originally Posted by astronobob
Yes Bill, I see that your Variable 'airgap' extender is looking rather close to being fully retracted - good piece of kit too. This distance set is achieving your desired flat field I assume ?
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Close, but not quite there, Bob. I think I need about another half or one mm. I'm having a mate with a lathe make a part that will enable me to shave a mm off the front face of the t-ring and snuggle the DSLR that little bit closer to the flattener.
One of these days I'll upgrade to something like a ASI1600MM-cool to go with the filter wheel I've already got, so I can get big-grown-up Ha photos. When that happens I'll be back looking at back focus (not looking forward to it, but I think you need a spacer rather than to shorten it). Just don't suggest an OAG!
Bill