An update on the Vixen R200SS review as I remove the primary mirror to do some cleaning.
The primary mirror was in a circular primary mirror holder which use 3 set screws and some padding to secure itself to the primary mirror from the side. Not sure how to remove the primary mirror holder, I clean the primary mirror with the holder... hope that it's ok and will not cause any problem in the future... crossed finger...
Anyway, at the front of the primary mirror holder, there are 4 sets of screws use for the installing the mirror clip which didn't touch the mirror surface as they are use to prevent the primary mirror from dropping out of the mirror cell if the side set screws failed to hold the mirror (touch wood). There is also a mirror clip mask that "hide" the mirror clip from the view. This should prevent the diffraction spikes cause by the mirror clip to appear on those bright star in long exposure astrophoto. I think the earlier version of Vixen R200SS don't have this mask as I had seen some Vixen R200SS user in other forum complaint about this. Anyway, the mask and mirror clip just cover the primary mirror by... may be less than 1mm in total, so the primary mirror didn't loss much light gathering power.
At the rear of the primary mirror holder, there are 4 threaded holes at the rear of the circular holder for the "pull" collimating screws. The collimating screws will "push" and "pull" the primary mirror holder during collimation.
The interesting part about the Vixen R200SS primary mirror is that you can see a bullseye pattern at the center of the primary mirror from the rear. Base on one of the review I read, the area where the bullseye pattern is actually partial aluminiumised, so that when you shine a light from behind (you must remove the rear primary mirror cover in the mirror cell to do this), you can see the bullseye pattern on the primary mirror from the front and when the laser collimator hit the center of the bullseye, you'll see the laser exist at the rear... quite an unique feature...
Anyway, since my primary mirror already center spot by meng lee, I didn't remove the rear primary mirror cover... hmm... may be I should remove it next time as it should cool the primary mirror faster.
Below are some pictures I took:
Vixen R200SS Mirror Clip and Mask
Vixen R200SS Primary Mirror Cell Holder with Rear Primary Mirror Cover
Vixen R200SS Primary Mirror with Mirror Holder - Front view
Vixen R200SS Primary Mirror with Mirror Holder - Rear View
Have a nice day.