There have been more than a few threads here and elsewhere talking about differential flexure, usually in reference to why OAG is the better way to go. One thing I’ve never seen is someone actually measuring it. On a very basic level, it would seem that a good general test would be to point your system at the lowest altitude you would normally image and take a long exposure, say 10 min. If guiding remained good through that exposure yet the stars in the sub are not round, that would certainly indicate that something is moving. No way to tell if it’s the image train, guide scope or anything else but it would demonstrate that there is a problem. If the result of the test is round stars then all is good and if you benefited from an OAG, it wasn’t because of DF but something else.
I could also imagine running two instances of NINA so that you can plate solve the main camera and guide camera. Start off pointing at the zenith, plate solve, step down to a lower elevation and repeat, down to your personal elevation limit. You could then take that data see if the pointing between the main scope and guide scope diverges with elevation.
Thoughts?
