Some experienced astronomers may have missed it in the beginners section, so restating the question here:
OK, so how do seasoned Vixen drivers get around using standard 2" filters in a Vixen system? I m talking photographically, not visually (visually, you add the Vixen 60mm to 50.8mm adaptor with compression ring and use a regular diagonal).
ALL threads in the Vixen photo tube system will NOT accept a standard photo filter thread. It's driving me nuts trying to figure it out, as I want to image H-alpha and O-III. I succeeded in "friction fitting" an H-a (Baader brand) previously, but I cannot get the O-III to fit (Orion brand) up against the T-ringinside the stepper ring.
Darned Vixen and their odd thread size!
I just don't know how short of taping a filter to the front of the flip mirror tube and using the through-tube for photos (but causing more vignetting not being full diameter)
Don't know about vixens, but I use a filter drawer just on the other side of my OAG. I looked at a VC200L a while back, and found this site interesting: http://www.mikesastro.com/equipment.html
Click on the VC200L, has a complete pulldown and comments on fixing triangular stars.
Maybe the owner of the site could help you with the filters question?
Decided to buy the Vixen 60mm to 50.8mm visual adaptor, use a GSO 2" dia. extension tube (I have several lengths) and a custom 2"full diameter T ring I had made. Can add the filter in the optical train somewhere at the adaptor