Focusing a refractor plus field flattener attached to DSLR camer

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#577237
Roger Dymock
Participant

Hi Richard,

Thanks for your comments. Ron Arbour’s article in this months JBAA reminded me that I have a Bahtinov mask suitable for my refractor. Bench testing showed that focusing for the ‘smallest blob’ using Live View is nowhere near as accurate as using the mask. Nick James suggested checking the focus across the whole image so I will try that using the mask asap.

I would rather it be a focus problemn than what you suggest which sounds more difficult to fix. Hopefully tonight or tomorrow night will provide clear conditions. 

Regards