by Dan Wright
"Old Smokey" is a worthy old orange tube Celestron 8" SCT that's been in the SJAA loaner program for years. It received its nickname, so the story goes, one fine evening when its anti-dew heating system caught fire (or at least got a little too hot). Vestiges of that heating system can still be seen, like archeological artifacts, clinging inside the OTA.
I took possession of it on loan from SJAA some weeks ago. It was in bad shape.
It had apparently been left out in the rain; water was sloshing around inside the OTA. I set it up indoors and left the back cap off for a week trying to dry it, but eventually had to finish the job by directing a blow drier on "low" into the back for an hour.
Both the corrector plate and primary mirror were filthy with dust and water spots, and the scope apparently wouldn't track. I posted to TAC asking the help of an expert, with the idea I'd overhaul Old Smokey to compensate SJAA for having been nice enough to loan it. More than one friendly TAC person responded, and on the advice of Mike Koop (leader of SJAA), I took Mr. Phil Chambers up on his offer of help.
One Saturday I was guest in P. T. Chamber's magic workshop as he expertly dismantled Old Smokey. First, using an electric multi-meter, we determined there was nothing wrong with the power supply. Those old RA tracking motors run on AC, so the power supply inverts 12v DC into AC. Also, with a twist of a knob, this power supply can change the base 60hz frequency smoothly up and down across a wide range to control the scope's tracking speed. I was impressed to see this 20-something year old circuit board faithfully modifying alternating current like that.
[ The reason I originally thought the scope wasn't tracking is I hadn't been locking down the RA, or during times I did lock it down, a period of gear backlash made me assume nothing was happening. Later I learned to take the slack out of the gears with a left-wise push before centering the object and locking. Using this trick, the scope tracks "like a champ". ]
Phil removed the corrector plate and did his best to clean its hard water stains using the recommended mostly-alcohol/one-drop-of-dishwashing-liquid solution with distilled water for a chaser. But he didn't make satisfactory progress until he broke out his secret bottle … methanol. Using that and Q-tips, the hard water stains were nearly vanquished.
Next he started to pull out the primary mirror. At this point I learned a secret of the master engineer or mechanic -- the importance of the proper grimace during crucial tasks. My accustomed grimace is a slight scowl with perhaps a tongue sticking out, but Phil demonstrated that by baring one’s teeth as in a growl, and squinting one’s eyes and knitting one’s brows tightly, the most stubborn C-ring can be coaxed loose and the most delicate primary mirror can be safely extracted.
He commented that it was dirtiest primary he'd ever seen. We took some digital pictures of it, and then cleaned it with methanol too.
He also pulled and cleaned the secondary mirror. He found the serial numbers on all three components showing how they'd originally been aligned at the factory, and it turned out the secondary needed to be rotated 120 degrees to match the original factory alignment.
In feats worthy of the best-provisioned shopkeeper, he produced odd and valuable implements such as: grease for the mirror axis (having just the right viscosity and guaranteed not to out-gas), flat black spray paint (for covering shiny bolt-heads inside the OTA), and three screws of precisely the right size and shape to replace the rusted old collimation screws.
Using a laser bounced off a spherical Christmas ornament at the end of the driveway, we collimated Old Smokey, and pronounced the scope good to go.
On a following weekend, we met up at Montebello. That was the night Paul Sterngold forgot his laptop and was limited to visual observing. He didn’t even cuss or swear about it either. Paul, Phil, and I had fun watching a transit of Io under skies that stood up to high magnification. The orange tube C8 was tracking and delivering remarkable images. Phil put the finishing touches on its collimation.
Celestron optics are legendary. Old Smokey is a great scope, still worth its salt even 20 years later.
On the SJAA web page (in the scope loaner program) Old Smokey is shown as number 6. It is not shown as currently available, and I think the page even shows Pat Whalen as currently having it … however, it’s in my garage, and I’m done with it, so somebody else ought to borrow it!
I’ll happily store it for SJAA in the mean time. It would be good for the Marathon … it comes with a Rigel quick finder (with a fresh battery), and a nice wide-field eyepiece as well as a high-power eyepiece and Barlow.
I’m done with it because I drove up to say hello to Sam at Scope City and incidentally bought a birthday present for myself … a shiny new 10” LX200 GPS (Yee-Haww!!). But that’s another story.
Here’s hoping to meet some fine dark night and recognize each other by voice or by vehicle!