The plan tonight was to start a new project but, despite the reports saying it would be clear all night, the high cloud rolled in as I was finishing my PA.
I have spent countless hours refining my 8” f/4 setup over recent times so I thought I’d take the opportunity in the small breaks in the cloud to point to Acrux and see what differences my work has made. During focus I achieved a FWHM about 0.8 better than I have ever been able to. This despite the reports saying the seeing was an 8. Very good but not a 10.
Collimation is 1000% easier and more reliable now since modifying my mirror cell. It really just needs a very minor tweak once setup. I can skew from side to side and up and down with no visible change. I have no doubt an auto collimator will prove me wrong but at this stage my laser is happy.
The image here is a single screen shot of my ASIair preview. I can still see the mirror clips because I haven’t made my mirror mask yet but overall it is significantly better than before.
The moon is back now so I’ll be refining further for the next 10 days or so. I’m pretty happy with the progress though.
Ray - I did document my mirror cell modification in the DIY section but I didn’t get much feed back so I didn’t bother putting up the focuser modification.
well done. F4 seems too tricky for my liking, but cant argue with the results I've seen posted on astrobin and the like for well collimate 8in F4 newts!
I chose an f/4 purely for the focal length. I have two SCTs for longer focal length imaging 1250mm and 2650mm respectively so I wanted my newt to be shorter. I did however also want large aperture. 200mm f/4 @ 800mm f/l seemed like a good compromise. If I’d known what was involved in getting it to work consistently I wouldn’t have chosen it. I do love a challenge and that’s why I’ve persevered but if I had my time again, I’m not sure if I’d make the same choice.
