Post by Chicago Astronomer - Astro Joe on Jul 18, 2013 3:29:12 GMT -6
Banged up 90mm Meade Refractor Gut Rehab Project
18 July 2013
18 July 2013
My $35.00 Ebay auction Meade 90mm Refractor has taken a beating in the three years I have used it, riding on top of the C11 - and solo on it's own on various Mounts....
From this....
...to this...
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[/url][/center]Full prior work on the 90mm here:
astronomer.proboards.com/index.cgi?board=Equipment&action=display&thread=2963
With the newer C102mm Refractor working for the Chicago Astronomer, the 90mm was regulated to the workshop - waiting for some warm weather to bring back it's luster. With temps in the city hitting close to 100 degrees..I think it's warm enough...
The two dents on the tube were from when the OTA fell off the C11 during a C.A. public session. The stupid generic dovetail clamps just did not hold on to the ring stems that C.A. Rick made me...and down to the concrete the tube went when I slewed the C11 horizontal to catch western targets at sunset. The Dew Cap cracked slightly and the adjustment screws on the rings left indentations...ugly ones. The scratches were probably from the same incident....but the tube looked raggedy and not suitable for Chicago Astronomer criteria of presentation. C.A. Rick made me the proper "Marzec" dovetail bases and the 102mm refractor that now rides atop the C11 is held on securely.
Back to the 90mm rehab....
The tube and glass works well and delivers sharp images, with just a bit of chromatic aberration, so it is well worth bringing it back to full service. Removing the focuser assembly, I power sand the finish off...
Using a random orbit sander and 60 grit, I remove the primer, (Blue) and the top coat (Silver), easily and quickly. Doing body work on the Chevelle all these years, has providing me with good metal working skills and finishing. I sand off the "Meade" logo with no hesitation...after all, what has Meade done for me?
The aggressive sanding has left me with a shiny aluminum tube and now easier to address the indentations - and I use a clamp to hold away the flocking I installed...
It was a challenge to knock these back out, considering they are deep enough to exclude C-clamps or direct tapping with a body hammer. I elected to use a ball-peen hammer and a blunted cold chisel to whack this inny back out...
Slowly and checking the progress often, I make solid contact with the indentation and bring it proud of the surrounding surface. Then with a 2" water pipe as a backing, I tap down the area flush. Some more sanding and some more tapping...and now -the hard to reach offending spots are now gone...
I take the time now to retouch the focuser with the Hammered Rustolium that provides a nice semi-rough finish...
I may replace this focuser with the one that came off the C102mm Refractor - which now has a great Dual speed Focuser - but we'll see.
Next....priming and painting the 90mm, but that is for another free night....
