Post by Chicago Astronomer - Astro Joe on Oct 26, 2024 7:40:51 GMT -6
Repair and Tune-up - Celestron 127mm Powerseeker Reflector
One of my youngest fans and Astronomy enthusiast "Milky Way Mina", let me know that the telescope she saved up for with her own money (Celestron 127mm Powerseeker Reflector) had an accident and fell over, breaking off the toe saver bolt in the Counter-weight shaft and a decent dent on the tube. With my very busy public schedule wrapping up for the observation season, I finally had some time to see what is going on here with this f/8 - 1000 Focal length scope....
Scuffed and needing a deep cleaning, I took on the job and disassembled the scope. It is of the "Bird-Jones" design, where a barlow-type of lens is placed in the focuser tube and needed to be removed for OTA collimation....
I set it aside for cleaning later.
Peeking inside, I felt that it certainly needed attention and I removed the Primary mirror... it needed cleaning...with particles and a haze on the mirror surface. (Some tend to state that leave the mirror alone, as a little grime does not interfere with the viewing and one could damage the mirror. (There is a large telescope in California with a bullet hole in the mirror and works just fine.) But, not my policy and it gets cleaned with cotton balls, light solvent for the stubborn spots and breath for a final wipe down....
I use a lot of cotton balls to lightly wipe the mirror, using only the weight of the cotton ball itself.
Immaculate, dust free and sparkling...
While the mirror was out, I used compressor air to blast the inside of the OTA...and a lot of debris came out.
Replacing the mirror back, it was time to collimate the primary and secondary mirrors. For Newts, I like to use a Cheshire eyepiece for coarse alignment and finish with a laser to dial in the proper light path degree...
Peeking thru the tiny hole on the Cheshire, the secondary looked good and centered in the focuser.
Next, the laser adjustments.
I like this Hotech laser, as it fits solid in focusers via expanding rubber seals, insuring dead center position.
(I also collimate the collimator at least once a year...and it is good.)
With the secondary set and locked, I moved my attention to the primary screws on the Mirror cell, tightening and loosening screws until the red laser dot was dead-center in the collimator. This OTA also has lock-down screws to keep the mirror in position...
And all looked good and snug
I lubed and oiled all threads and gears for smooth action and rust prevention...
Also cleaned the Bird-Jones Barlow glass...
It was about 4:00 am when I reassembled the OTA and did a star test on collimation. And I got some pretty good concentric rings confirming proper collimation. Presently, the early Fall sky is loaded with celestial delights and I spent some time observing: Mars, Jupiter, Sirius and the Orion Nebula with this 127mm scope...and not only did the images come in sharp, but it was fun peeking through this scope.
I then worked on the Counter-weight shaft, drilling out the broken bolt, (Pretty deep) and rethreading the Inside for a new Toe-saver knob...
All is solid and ready for return to Mina this weekend with a Chicago Astronomer logo and back to exploring the cosmos...
Astro Joe