Glatter Tublug Question
Posted 20 January 2013 - 12:09 PM
Posted 20 January 2013 - 12:20 PM
If so, then your axial alignment should be fine and any subsequent star alignment should also be fine (as the star alignment/assessment only verifies the primary/optical axis alignment).
If you loosened the center mounting screw of the secondary holder, it's possible you've changed the rotational alignment of the secondary mirror. Have you tried looking into the empty focuser drawtube to assess the concentricity and roundness of the secondary mirror relative to the bottom edge of the drawtube and the reflected edge of the primary mirror?
...I fiddled with it moving it sligthly while the center screw was loosened and I was able to get the reflected light around the hole but when repeating the collimation the refelected donut and light are not together.
FWIW, it takes a pretty severe rotational error to impact the axial image performance.
Posted 20 January 2013 - 12:28 PM
Posted 20 January 2013 - 12:30 PM
Posted 20 January 2013 - 01:06 PM
From my tuBlug instructions, which should have come with the tuBlug : "The diverged beam impact on the primary may be irregular and not centered, but this does not matter. ."
This is true as well of the reflected laser light on the tuBlug screen. The diverged beam is an enlarged version of the somewhat irregular cross-section of the original laser beam. The irregularity of the beam perimeter does not matter for the collimation; all the rays in the primary-reflected beam are still parallel.
Posted 20 January 2013 - 04:43 PM
Posted 20 January 2013 - 04:47 PM
PS I tried to get to Howie Glatter's website but there is an error so could not ask him or look up the information.
Howie makes the best stuff, and has the worst web site in the business. (I do love you and your stuff, Howie.)
When his site comes back up, note his e-mail address and phone number. He will answer e-mails quickly and is helpful and fun to talk to on the phone.
Posted 20 January 2013 - 10:34 PM
Posted 21 January 2013 - 07:34 AM
Posted 21 January 2013 - 01:42 PM
Yup, Howie makes the best stuff. I had the same off-center for the line-y stuff, but my center spot was dead-on, and what-do-you-know...so was the collimation later that night. Amazing!
Posted 21 January 2013 - 04:13 PM