Picked up a C11 vintage 1990
Posted 08 November 2012 - 01:24 PM
Good.. Mechanically very sound
Optics are in good shape after cleaning.
Got it at a good price.
Bad.. Tube is scuffed up and scratched but not dented(good).
A previous attempt at cleaning left OTA in a funny state.
Problems I found with the OTA
1. No cork on the lip of the cell.. Just glue. corrector was set ON the glue. *BLEEP*??
2. New cork on the retainer was put on very hap hazard.
3. Retaining ring screws were TIGHT...
4. No grease on the mirror baffle!! It was cleaned up very well except for two blobs of grease on the side of the mirror???
I'm thinking the scope was taken apart to be cleaned/ serviced and was put back together at a later date. by someone who didn't really know what they were doing.
It's all apart and I cleaned the primary. Coating looks very good. Corrector has a bit(lot) of glue around the edge that needs acetone for removal. Picked up some nice 1/16" cork automotive gasket for the corrector cell and retaining ring.
I have three different greases for the baffle tube.
Slick 50, Mobil 1, and vacuum grease. Slick 50 has NO odor like the vacuum grease but is a much better lube. The Mobil 1 is nice but does have some odor.
I'll take some pictures of the scope and process this evening.
Posted 09 November 2012 - 07:02 AM
Posted 09 November 2012 - 12:30 PM
I made a little washer to fit over the centering button about 1mm thick. That will give plenty of adjustment range for the secondary. The cell gets distorted at the screws and the range of adjustment gets smaller and smaller.
Posted 10 November 2012 - 01:17 AM
Did a rough star alignment. Images looked pretty good, inside and outside focus rings looked pretty good alignment wasn't perfect, but close. One issue is the grease on the baffle tube is too heavy and thick. The foucusing is very stiff. This scope has a very tight baffle tube clearance. No image shift at all. Still needs a good bit of mechanical work.
Posted 10 November 2012 - 03:09 AM
Posted 10 November 2012 - 08:27 AM
Posted 10 November 2012 - 04:13 PM
Going to try and set it up this evening on something sturdier than the deck table.
Posted 10 November 2012 - 06:56 PM
Posted 10 November 2012 - 07:46 PM
Bob, great to see those giant, sand-cast forks! Wonderful old scope.
Amazing that these are essentially the same telescope made some years apart, wearing different livery. I'm planning a trip to see a blue-and-white C10 in a rooftop observatory. Watch for the thread!
Posted 11 November 2012 - 04:48 PM
Posted 21 November 2012 - 10:30 PM
Foscusing was very stiff and had a lot of hysteresis. Used just a dab of Mobil 1 grease smeared around the tube (just a little) VERY nice. Great feel now. No noticeable shift. Regreased the dec bearings, made a weight for the counterweight bar, adjusted the worm gear for backlash, polished the tube and just cleaned up a bunch of things.
It was a real joy to use this evening. Problem is,seeing is about a 2 right now. Only had to do a tiny tweak to get the collimation right in line. The C11 is really coming together. Never been a big Celestron fan, but I really like this C11. It needed some love has good optics and has personality.
I don't even want to paint the scratched tube.