Collimation of an FS-152

Started by lthaxton, 07/30/2008 04:51AM
Posted 07/30/2008 04:51AM Opening Post
I picked up a Tak FS-152 and while I have collimated every other Tak I have owned, I never had to touch my old FS-152. I own the Tak collimation scope and would be interested in hearning from others who have had to adjust their FS-152s.

thanks!
Posted 07/30/2008 05:08PM | Edited 07/30/2008 05:19PM #1
I did one of these for a friend on Monday. It was pretty
simple with 2 people and the Tak collimation scope. This
OTA had 3 screws at each of the three positions -- the
two large head outer screws "pull" and the small one in
the middle "pushes." (Oddly, the manual only shows two
screws at each position.) He had the lens off to TNR
for adjustment, hence the collimation exercise upon
re-assembly. Haven't done a star test since collimation.
The process was similar to any other refractor, once you
figured out about the three screws.

The best collimation was only slightly different from having
the lens flat against the OTA tube. (Good machining, apparently.)

I've seen other refractors where the optimum star test
collimation is quite different from the Cheshire
collimation. This can happen if the lens spacers are
not equal thickness, or if a lens element is slightly wedged.
So the Tak collimation scope will get you close, but
(theoretically speaking) you may still need to tweak
it under the stars.