Hi Mark,

Peter etal have more experience of this than me as I’ve only just got a focuser so you might want to take what I say with a pinch of salt….

The way I see it you need to move far enough from focus to get hfr’s that produce a V. Peters said how he does it and from his graph he gets a nice V. Me with my simpler equipment I’ve yet to get a proper V but I am developing an understanding of how this works now so maybe I will come up with an initial steps setting etc which works.
However I suspect that to get enough of a change in hfr I will stray into donut territory which leads to problems. Now I believe to handle those I need to pick/tweak the appropriate SEP settings. To do that I’m aiming to take some images that are out of focus to see what helps count the whole donut rather than just little bits. I’ve tried reading the ‘do not panic’ guide to SEP but obviously that’s for phd level people so I’m going to have to do some poking until I get an idea…unless of course someone else has already worked it out.


Regards

Nigel

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