Hi all
Decided to upgrade my old Meade Cometracker's focuser, itself quite reasonable, but not quite fine enough for the very small focusing tolerance a F3.6 system has. I ordered the Bintel low profile crayford 10:1 model after measuring backfocus to make sure it would work. It arrived promptly, and very well packed.
I couldnt use the original focuser mounting screws as they were too short with the new focuser's larger thicker mounting plate, but had others that didnt have countersunk heads but as the new focuser has a removable head I loosened the grubscrews for it and rotated it so it would clear the screw head, thats why it appears at a 45deg angle.
Note, plenty of backfocus, the camera is focused at infinity as you see it there. The strap is the "highly technical" way I hold the scope in a wooden cradle along with a 3 inch catadioptric "focal" brand Halleys comet special $70 scope that serves as a guidescope
Before drilling new holes I had to remove both the primary mirror, secondary and correctorplate, IE completely dissamble the optics. For reassembly I fitted the correctorplate/secondary assembly, then looked through the focuser and rotated it by hand till it "looked right" as close as I could get it by eye. I had a naser collimator I could use to get it closer once the primary was on. I then fitted the primary mirror in its cell, and was amazed to look through the focuser and see that it looked in pretty darn close collimation. After it got dark, it was cloudy so used a distant streetlight, that was small enough to show diffraction rings at high power, and bugger me, collimation was almost perfect. I couldnt believe Id completely dissasembled/reassembled a F3.6 reflector optical system and had it in near perfect collimation
I slightly tweaked it till diffraction rings were as even as possible.
2nd image is when cloud thinned enough to at least get a starfield. Stars look reasonably sharp expect perhaps right in the corners, not bad for a $300 telescope
The Baader MPCC helps though, it is somewhat worse without that. Attaining good focus is much easier now, taking test pics and moving the fine focus knob slightly and so on till stars are as small as possible. Now all I need is clear skies to do some proper DSO imaging
Scott
