RC8 Primary collimation?

[NilRecurring]

I've adjusted my RC8's moonlite focuser such that the laser beam falls on the center spot on the primary. I then adjust the secondary such that that the beam folds back on itself. All of this is spot on and I'm confident that the secondary is collimated as well as the focuser.

But when I attach the holographic attachment to my laser I get the following pattern. Notice that the reflection from the primary is slightly off-centered (note the small arrows). Does this indicate that the primary is not collimated properly?


I would massively appreciate any advice on this!

[stevous67]

I understand Moonlite have a nifty adjustment available in their focuser to align it to the centre of the secondary, but remember the focuser sits on the same movable plate as does the primary. So any adjustment of the primary affects this alignment.

James has a blogg with ideas on collimating these guys, maybe look there for some more hints (deepspaceplace). Btw, those lasers are great to get close, so see how it pans out with a star test to finish the job off,

Steve

[TR]

There are a series of videos you may find useful.

Ritchey-Chretien Collimation: Step 1 of 3
http://www.youtube.com/watch?v=2EC5N5bfB9A

Ritchey-Chretien Collimation: Step 3 of 3
http://www.youtube.com/watch?v=RUOza5EHRNg

Ritchey-Chretien Collimation: Step 3 of 3
http://www.youtube.com/watch?v=25vR-MbCf0M

The videos use the Circular holographic attachment, but the squares should be similar in theory.

Terry