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Old Smokey is Back On Patrol

Dan Wright


 

"Old Smokey" is a worthy Celestron 8" orange tube SCT that's been in the SJAA loaner program for years. Its nickname was earned, so the story goes, one fine evening when the anti-dew heating system caught on 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 sloshed around inside the OTA. I set it up indoors with the back cap off for a week trying to dry it, and eventually had to finish 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 hard water spots, and the scope apparently wouldn't track. I posted to TAC asking the help of an expert, with the idea I would 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 accepted a certain Mr. Phil Chambers' 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 R.A. tracking motors run on AC, so the power supply inverts 12v DC into 120v AC. Also, with a twist of a knob, it modifies the base 60hz AC frequency up and down across a smooth range to control the scope's tracking speed. I was impressed to see this 20-year-old circuit board faithfully modifying AC frequency like that.

The reason I assumed the scope wasn't tracking is that, when observing, I hadn't been locking down the R.A., or if I did lock it down, several seconds of gear backlash made it seem like nothing was happening. Later I learned to take the slack out of the gears with a left-wise push before locking the RA, and/or to approach objects solely from the left before locking. Using these techniques, the scope tracks "like a champ."

Anyway, Phil pulled off the corrector plate and did his best to clean its hard water stains using the recommended solution of pure alcohol with one drop of dishwashing liquid and distilled water for a chaser. But he didn't make satisfactory progress until he broke out his secret potion ... methanol. Using that and Q-tips, the stains were almost completely vanquished.

Next he began to pull out the primary mirror. Here I learned a master engineering secret $#8212; the importance of the proper grimace during crucial tasks. My accustomed grimace is a slight scowl with tongue held sideways, but Phil demonstrated that, by baring one$#8217;s teeth (as in a growl) and squinting with tightly knitted brows, the most stubborn C-ring can be coaxed loose and the most delicate mirror extracted.

Once we had the primary resting safely upright on the bench, he commented it was the dirtiest one he'd ever seen. We took some digital pictures of it, and then cleaned it carefully with methanol too. We didn't get it perfect, but it was a great improvement.

Next (and with the proper grimace) he removed and cleaned the secondary mirror. We found the serial numbers on all three optical 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 alignment.

In feats worthy of the best-provisioned shopkeeper, he produced rare and valuable implements such as: (1) grease for the mirror axis, having just the right viscosity and guaranteed not to out-gas, and (2) flat black spray paint for covering shiny bolt-heads inside the OTA, and (3) screws of precisely the right size and shape to replace the rusted old collimation screws.

For his next trick, he bounced a laser off a spherical Christmas ornament at the far end of his driveway for a collimation target. After that, Old Smokey was pronounced good to go.

On a subsequent weekend we met up at Montebello. Phil put the finishing touches on orange tube C8's collimation. It was tracking and delivering remarkable images.

That was the night Paul Sterngold forgot his laptop and was thus limited to visual observing. Paul didn't even cuss or swear about it either. By the way, when I originally posted this story to the TAC list, Paul followed-up with:

Ouch! Thanks for outting me. Now my imaging buddies won't have anything more to do with me.

Paul, Phil, and I had fun observing a transit of Io under skies that stood up to high magnification. Celestron optics are legendary. Old Smokey is a great scope, and still worth its salt.

On the SJAA web page, in the scope loaner program, Old Smokey is shown as number 6. The web page might not show it as currently available, however it's in my garage, and I'm done with it, so somebody ought to borrow it! I'll happily store it for SJAA in the mean time. It comes with a Rigel quick finder (with a fresh battery), a wide field as well as high power eyepiece and barlow, and a set of those celebrated Celestron anti-vibration footpads.

The reason I'm done with it is because I drove up to San Francisco to say hello to Sam at Scope City, and incidentally bought myself a new 10" LX200 GPS (Yee-Haww!!).

I thought I had made appropriate sacrifices to the weather gods, to appease them for having bought a new scope, but as I write this, the Messier Marathon looks to be clouded out, so perhaps my offerings were not sincere enough.

Anyway, here's hoping to meet you under very dark skies, and recognize you by your vehicle, or your voice, or the funny ski-hat you wear!

 


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