NeilW
30-03-2011, 10:30 AM
Hi folks,
I have an 8" SW dob and as many here have done, replaced the existing primary collimating screws etc. with stronger springs and some Bobs Knobs type thumbscrews. This of course has resulted in the primary mirror being pushed forward about 1.5cm. Now I find that especially with low power eyepieces such as a 20mm I can't rack the focusser out far enough to get focus. I have to pull the actual eyepiece out a little way and lock it in place.
I have a Moonlight Crayford focusser, with as many spacer plates as the longest screws will allow, but I still can't focus with the eyepiece in the correct position. Has anyone else had this problem and have a solution? I've considered going back to the old SW hex screws for collimating.
Thanks,
I have an 8" SW dob and as many here have done, replaced the existing primary collimating screws etc. with stronger springs and some Bobs Knobs type thumbscrews. This of course has resulted in the primary mirror being pushed forward about 1.5cm. Now I find that especially with low power eyepieces such as a 20mm I can't rack the focusser out far enough to get focus. I have to pull the actual eyepiece out a little way and lock it in place.
I have a Moonlight Crayford focusser, with as many spacer plates as the longest screws will allow, but I still can't focus with the eyepiece in the correct position. Has anyone else had this problem and have a solution? I've considered going back to the old SW hex screws for collimating.
Thanks,