Quote:
Originally Posted by Paul Haese
Star testing an RC and doing the required final adjustment will involve moving the primary. If all your preliminary work is done properly then it should be an ever so slight star test adjustment.
Just to be clear you need to first align the focuser with the secondary mark (use a laser for this and use the focuser adjustment screws or a focuser collimation ring), then the secondary to the primary and then finally align the primary to the secondary (all done with a Takahashi Collimation scope).
I would recommend doing the adjustments when the scope is on the mount. Any knocking or bumping must be assumed to affect collimation and hence even a new scope will require collimation. Be also careful to just lightly tighten screws. If you apply too much pressure, you will cause pinching of the optics. I also therefore don't agree that you should never touch the primary. The reason the screws are not glued tight is because it is expected that you will need to adjust them to obtain perfect collimation.
It can be a little tricky to get collimation right but the results can be fantastic when you do get it right. If you can still get it, there is a video from Ken Crawford which shows how to collimate an RC with a Tak scope.
Hope that helps.
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Hi Paul
Thanks for the response. I have tried many procedures, the Takahashi procedure has been successful in the past but recently I noticed guide stars had tails. I checked out and followed YouTube procedures (Stephen Kirk and Allen Mitchell) and digested the OPT and DSI procedures too.
I’m thinking that I may need to persevere with the DSI procedure for the final stage because I am reasonably confident that the laser collimating (using the Howie Glatter) is pretty close.
I was just unsure what part of the train needed the adjustment.
The other concern is the laser collimating is completed indoors on my desk, then I re mount my OTA onto my mount and then reattach my cameras so that is likely to change things a little.
Cheers
John