开云体育

I am going to post this here since I've requested help elsewhere.? Please delete if not appropriate.

I am having a major problem trying to achieve focus (without coma) on my images.? I have the backspacing of my Esprit 120, with SW 0.77FR and 2-inch ZWO filter wheel set at 56mm and I cannot get focus and the focus tube of the scope is close to 200 mm (almost as far as it will go in).? Even at that point I still cannot get stars to focus and I run out of room on the focus tube.? I've then set the spacers to 51 mm and I can achieve focus BUT now each corner of the images are showing coma's facing each corner, which means to camera is too close to the FR....HELP!!

FYI; the SW-FR requires a 90+mm backspace but if you use the included spacers (which I am) you only need to stick with the 56mm spacing afterwards.? I never noticed the problem before until I started doing mosaics and now see the image when trying to create the mosaics.

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ANY HELP will be appreciated.? I am at a complete loss here and I find the advice on the Losmandy group tends to be the best.