Auto focusser or Bhatinov mask? in Imaging - Discussion Posted October 23, 2018 13 minutes ago, spillage said: What scope do you have? I have a cheaper skywatcher focus motor and love it. You can remotely focus and make very fine adjustments easily. You can run the auto focus then you either change filters or your subs start to look worse. I will not constantly check and adjust the focus for you over the entire session. I have a SkyWatcher ED100 and currently use a ZWO ASI1600MC-Pro so no filters to worry about. 14 minutes ago, ollypenrice said: I stick to manual focus because I hate things going wrong - and autofocus systems do go wrong. I host several of them in our robotic sheds. They do mostly work but when they don't they don't. And they're expensive to set up as well. However, for me the B-mask is only the first step. Once on target I check the FWHM values of a star in the field and adjust accordingly. I think the big advantage of robotic is that you can go to bed while it runs the sequence. If you don't need that advantage then manual has a lot going for it. Olly It sounds like a fairly slow process Olly - either taking subs or using some kind of live view while manually adjusting the focus to minimise the FWHM? Do you find this more accurate than a B-mask?