Way down telescope way pt. 3

When last we spoke, I'd succeeded in taking my Meade 645 completely apart, sanding it down and applying a coat of primer. After letting it dry/cure/rest for a couple of days, I began to apply the final color paint on top of the primer--Duplicolor Claret Red Metallic:



Pretty, no? I applied two light coats then set it aside to dry, with the intention of sanding lightly the next day and applying two more light coats. Then the winds came. For well more than two weeks, it was far too windy to spray paint, so I turned my attention to the telescope mount and tracking motor.



I cracked open the old motor drive to see if I could figure out a way to make it functional again. I bought the telescope used from Texas Nautical in '83, with the drive clearly described as "not working." I remember that clearly, because as a 13-year-old about to spend more money than he ever had in his life, I simply didn't care. It was more telescope than I'd dreamed of, and I didn't really understand the value of a tracking drive. So I bought it in non-functioning condition. Later, out of curiosity, I plugged the motor in. It came on with a clockwork whirr. Neat, I thought. Maybe it works after all. So I set it up on the front porch one weekend morning and let it run to see if it would track--or rather, move on its own. Six hours later I unplugged it in disappointment. It hadn't budged. That was maybe 25 years ago, and I hadn't plugged it in since.

Thanks to the kindness of the online community, I've now got a scanned copy of the Meade user's manual for the 645, which I'd never had before. There's a nice diagram of the drive system included, as well as a drive troubleshooting section. I found this helpful, and decided to plug in the drive once again to see if I could diagnose the problem. The R.A. override knob has always worked, I should point out. The plug prongs were pretty mangled, so I worked them back into shape with a pair of pliers and plugged it in. The whirr returned. I adjusted the setting circles to 0 and marked the R.A. override knob as Meade suggested and sat back to wait.



Danged if the thing didn't work. The R.A. override turned as supposed to, the motor whirred along and the tube moved. How accurately, I didn't know, since I bumped the tube a couple of times and had to start over and eventually it got too late to continue. But the crazy thing was working! The motor did change tone a couple of times, as if it was struggling, so I suspected the gears need to be re-lubed (after 25 years? You think so?).

A few days later I returned to the motor. The cover had a bunch of dust and dead insects inside. Ugh. The worm gear was pretty gunky. What at one time was, I suspect, lubricant had turned over the decades into a thick sludge. Amazing that it'd turn at all. I set to work with a toothbrush purchased specifically for the job (I was afraid to use any degreasers other than detergent for fear of damaging the worm) and managed to get the worst of the nastiness out of there. Then, lo and behold, I just happened to notice one of the motor's wires crushed flat. It must've happened during the original assembly, when the cover was bolted over the motor.



Might that be what's caused the tracking motor to run/not run all these years? Since there was plenty of excess wire, it was simple work to snip away the bad section and re-splice. I don't know if that had anything to do with the motor's not running, but it didn't make any sense for me to not effect this repair. Having previously de-gunked the worm gear a respectable amount (not 100 percent clean, but most of what's left was just discoloration) I applied white lithium grease with teflon. Then I hand-cranked the RA adjustment knob until ungreased gears lined up with the worm and repeated. By the time I'd made the full 360, the tell-tale squeak accompanying my RA turning had faded almost completely. So far, so good.

Eventually, the insane winds that had been blowing non-stop for two weeks finally died down over, and I was able to get out and spray more layers of paint onto the 645. Spray and rotate, spray and rotate. Wait to dry, repeat. The next day sand, and repeat the process. Curse like a sailor when one can decides to start spitting for no reason when it's still 90 percent full. Curse curse curse. Let dry. Sand and sand again. Repeat paint application with a new can. Finally reach the point where I say to myself "That's probably enough paint." Apply clear coat. Let dry overnight, then sand with 1000 grit paper. Apply final coats.

At this point I want to make good on my promise to explain why I didn't apply enough primer. Turns out that 220 grit sandpaper was too rough. Or perhaps the 80 grit before that, which I used to strip away the old paint. Seems that the rough sanding left grooves in the tube that weren't entirely visible when I primed, but really stood out once metallic paint was applied. Light sanding and re-painting did little to remedy the situation, and I wasn't about to go through the time and expense of sanding everything back down and starting over. I'll live with it. Just remember kids: Primer is your friend!

When applying the final clear top coat, I vigorously cursed the gnats that come out of nowhere on a kamikaze mission. Then I fled into the house with still-tacky scope. The next day, I sanded with 2000 grit paper, wiping after ever stroke since wet sanding was not an option. The tube looked good, but oddly streaky in places from the sanding. I polished with Lemon Fresh Pledge. WOW! It looked better than good. Streaks had vanished, and the metallic paint really, really shone.

It was time to flock the tube's dull innards, so I got out my roll of Protostar flocking material (think adhesive velvet). Flocking, you see, is intended to cut down on light scatter and improve contrast during viewing. There's some debate over its effectiveness, but my scope needed something to improve the dull gray inside of the tube. The custom cut option Protostar offered came from a 30" wide roll, which was perfect for me, since my tube is exactly 30" long. I immediately discovered that rolled flocking material can attract lint, dust, cat hair and an ungodly number of bright white flecks of... stuff like nothing else. So I whipped out the sticky tape and spent the next hour trying to get it all picked off. I was mostly successful, but man, was that tedious. Then I clothes pinned the flocking material to the inside of the tube, marked it for a 1" overlap and trimmed off the excess (about 3" worth. I ordered extra to guard against coming up short). Then I rolled the material up on a thick wooden dowel, peeled back the wax paper backing, and began installing. Here's a before shot:



You'd think that since it sticks to the wax paper like nobody's business, it'd really hang onto the tube. Eh, not so much. At least not until you get about half of it laid down, at which point the paper is clogging up the tube so much you can't really reach anything. So the logical thing to do is tear away the paper, right? Just make sure when you do this, you don't allow the sticky side of the flocking material to come into contact with itself. In the immortal words of Elwood Blues, "Epoxy. Strong stuff." When I finally managed to separate it, somehow the adhesive had stripped from both sides of the affected patch. Where'd it go? Maybe I inadvertently created a dimensional rift. In any event, I finally got it all laid in, and despite my struggles, it looks pretty good. Here's the after shot:



With the tube completed, I turned my attention to the spider. In the image below you can see the secondary mirror spider, along with three bolts. To the left is one of the original specialized aluminum bolts used to secure the spider to the optical tube. As I mentioned earlier, one of the bolts snapped on me a few years back, and I hadn't had any luck finding a replacement. So I made one of my own (center). I picked up some thumbscrews from a local hardware store and using a hack saw, a file and a 6x32 drill tap, cut the thumbscrew into a passable substitute. Then I primed it and sprayed everything matte black. I can't take all the credit, though--this guy restored a Meade 826 a few years ago and faced some of the exact same issues I'm dealing with. My secondary housing didn't appear to be in as bad of shape as his, but in a few years, I'll probably spring for a whole new spider vane/secondary rig. Probably a new secondary mirror as well, as mine is starting to show some streaks.



The spider fastener was the single biggest issue I had to deal with to get the scope usable again. And I'd triumphed!

The time came to put everything back together. The primary mirror went in easily, as did the spider. Suffice to say, it was wildly out of collimation. I had to wait a few days until the sight tube/cheshire collimation tube I ordered came in, and then I had Apollocon intervene, so collimation had to wait. In the meantime, I painted some black trim and installed the spotting scope and focuser. I took the two aluminum end rings, which had gotten pretty dull and dinged up, and wet sanded them with 2000 grit paper. That perked them up nicely. The felt lining the cradle rings had become hard and brittle, so I stripped this out and used a utility knife to chip away the petrified glue. Then I sanded with 400 grit paper to smooth the inner surface somewhat. I picked up adhesive felt sheets from Hobby Lobby and cut strips which I applied to the rings (although in hind sight the leftover flocking material probably would've done the job as good or better).

I returned the end rings on the scope and used pieces of flat cork to try and avoid having to glue them on. Well, the cork secured them on all right, but even the thinness of the "shim" was enough to distend the end ring. And, I feared it might eventually warp the tube as well. So I pulled both end rings off (no small feat--the cork held them on tight) and added a strip of that adhesive felt to each ring. This proved to work much better. The rings slide on more smoothly, but still maintain a firm grip without any distortion. It may get loose later on with use and age, but I can always add more strips of felt along the interior of the ring.

I reattached the mount to the pier, and set the OTA in the cradle rings. Then I added the counterweight. And I plugged it in. After four hours, a quick setting circle check showed movement of.... four hours. Obviously, that's not a test for precision accuracy, but after having this scope with no tracking whatsoever for 25+ years, the prospects of having a working drive leaves me positively giddy.

Oh, I also re-painted the black motor cover.

For collimation, I took the whole thing onto the back patio and set to work. Wow. This thing was waaaaay outta wack. The secondary mount in particular wasn't playing nice, so I had to take it completely out to work on it. The adjustment screws wouldn't turn, and it took a bit of coaxing before they'd cooperate. The secondary mirror looked as if it'd come slightly dislodged, but the ancient housing was corroded and brittle so that I couldn't get it apart to address that issue. The mirror wasn't loose, just slightly out of position. And on closer examination, the secondary mirror was in somewhat lesser condition than my original evaluation. The whole secondary/spider shebang will definitely be due for replacement eventually, but I can coax a little more mileage out of them yet.

Using the sight tube I got the secondary mirror positioned and aligned, then the cheshire made the primary collimation a snap. I was very happy with how that went. There's still a slight discrepancy in the collimation when looking through the sight tube--the two innermost circles are somewhat off-center in regards to each other, an effect I ascribe to the secondary mirror being slightly out of position, forcing the secondary mount to hold a steeper angle than ideal in order to compensate, thus showing a larger silhouette than ideal. In any event, I couldn't do anything about it at that point, and judged it wouldn't have a dramatic impact on my initial viewing anyway.

Holy moly... the scope, she is done! For reference, her is one of the few images I have of it pre-restoration:



And the finished product. Behold the Maroon Barsoom:



And the wide-angle view:



And an infrared view of your humble telescope restorer along with the fruits of his labor, in glorious false-color, just to shake things up a bit:



Join us next time for the obligatory "first light" report!

Way down telescope way pt. 2

Last week I shared the genesis of my current telescope restoration project, in which I expound (in my usual verbose way) how I came into possession of a 6" Meade 645 Newtonian reflector telescope and the subsequent years of use, abuse and neglect it suffered under my ownership. Lest any of you jot this down as one of those "He'll talk a good game, but not actually do anything about it" scenarios, I offer photographic proof of my get-off-my-duffedness (note how old and fat I look in this image. Oh, the sacrifices I make for you people):



Suffice to say the tube had suffered a lot of cosmetic damage over the years, but nothing terribly serious. The felt (or rather, the pitiful remains of felt) lining the rings which hold the optical tube assembly (OTA) to the mount had actually bonded with the paint on the tube. When I opened the rings and tried to remove the OTA, the process actually peeled some chunks of paint away--as well as a 1"x2" piece of the sonotube OTA's outer layer. The depression wasn't huge, really, but it may as well have been a crater to me. I trimmed it back some and glued it into place. Ugly, yes, but hopefully all will be made right in the end.

That out of the way, I turned my attention to the disassembly of the OTA. The tube is in serious need of repainting, and probably the worst thing I could do to the optics would be to try and repaint the thing with everything in place and in danger of getting big blobs of paint on them. One of the bolt/brackets attaching the spider (the assembly which holds the secondary mirror) to the OTA snapped a few years ago during a move, so that needs to be replaced. Fortunately, the three remaining bolts unscrew easily enough and I'm able to remove the spider successfully. There's a significant amount of paint flaking and peeling from the spider, but no serious corrosion anywhere. I could probably justify replacing the spider, but its in good enough shape that this feels more like an extravagance. Below is a shot of the spider, a close-up showing the paint flaking and mounting cracks, and finally one of the secondary mirror itself. Happily, the mirror looks to be in almost perfect condition.





The focuser and spotting scope come off next, and then the primary mirror. The screws come out of the primary mirror assembly easily enough... but the mirror doesn't budge. I've never taken it out before, and it had probably remained there, unmolested since it was first installed at the Meade factory. It took a bit more muscle than I was expecting (or entirely comfortable with applying) but finally the mirror assembly popped out. I was quite happy with what I found. Other than an accumulation of dust, the mirror looks in prime condition. Other than the broken piece of the spider, the OTA components are in great condition. I mean, just look at this mirror:






So now comes the actual restoration. The inside of the tube, originally painted flat black, has become more like a dark gray over the years. I don't feel all that comfortable (or enthusiastic) about repainting the inner tube, so I ordered flocking material from Protostar. Since my 645 is a 30" tube, their "cut from the roll" option was perfect for me. The flocking came in the other day, and I laid it inside the tube for a sort of dry run. Perfect fit, with a 2" overlap at the edges. I'm feeling good about this choice.

Before I can flock it, however, I have to repaint the tube. Before I can repaint, I have to sand it down. So I set to work with 80 grit sandpaper. It was very dusty work, I can assure you.



Amazingly enough, the paint came off with considerably less effort than I expected. For the various nicks and gouges too deep to be painted over, I used carpenters wood putty to fill in the gaps, and also applied generous amounts around the wounded area I mentioned above. After letting it dry overnight, I sanded everything smooth with 220 grit paper.



Get used to the phrase "then I sanded it down..." because it's a recurring theme. Once I finished and had the putty smooth and flush, it was time to apply primer. I ran a wooden dowel through the tube, packing crumpled newspaper around it so that I could suspend the tube between two saw horses and rotate it as I painted. I sprayed on two coats of primer, and let it hang in my office to dry.



Next time, we'll discuss why two coats probably wasn't enough. But hey, live and learn, right?

Way down telescope way

Like many folks of my generation, as a child I wanted to be an astronaut when I grew up. Somehow I got it into my mind that astronauts and astronomers were similar professions, although one never seemed to actually get into space. Both had an eye on the sky, and I wanted to be one or both. Even before Star Wars turned me on to science fiction in a big way, I was fascinated with space and the solar system. Telescopes were cool. Alas, I was soon to find out that to have even a remote shot at becoming either an astronaut or astronomer, I'd have to eat, drink and sleep in a world of relentless number-crunching. To say that my mathematic skills are feeble at best would be an insult to all the feeble mathematicians in the world. So that particular dream was DOA long before I even knew it was feeling sickly.

My family wasn't of a scientific inclination--for my love of space, I was pretty much on my own at home. Fortunately, I had a next door neighbor, John Story, who was a space buff and a long-time member of the Houston Astronomical Association. He had a quality refractor--I have no recollection of the make or even aperture--that he'd set up on summer nights and show me all sorts of skyward wonders. John Loessin, the adult son of one of my elementary school teachers, had one of Celestron's early 8" Schmidt-Cassegrain telescopes that he'd use for visual observing as well as astrophotography. So I had some quality scopes around me. Naturally, I had to have my own.

I don't remember the details very clearly, but the general outlines of the story are familiar ones: In 1983, at the awkward age of 13 I mowed lawns all summer and amassed the princely sum of $300 plus change in my telescope fund. This was the most money I'd ever had in my life, suffice to say. Clueless about telescopes beyond the fact that there were different kinds, they cost a lot and they made far-away things look bigger, I set off to purchase one. Fortunately, Mr. Story pointed me in the direction of Texas Nautical Supply in Houston, which was--and remains--one of the premier astronomical resources in the state.

Somehow, I talked my dad into taking me. Or rather, he probably had business to conduct in Houston and consented to have me ride along. My first impression of Texas Nautical was that of a classic natural history museum, only instead of giant dinosaur skeletons on display, they had giant telescopes. In my memory, the display floor is choked with monstrous, drool-inducing 20- and 30-inch planet-killers, although in hindsight 10' and 12" scopes are the most likely sizes populating the upper end of their wares. Still, it was might impressive to me, an ignorant teen who'd hoped to head home with a 2.5" refractor.

A refractor was my scope of choice, simply because that was the "classic" scope in media, and what I was most familiar with thanks to Mr. Story. But $300 isn't a whole lot of money where telescopes are concerned, even back in 1983. Luckily, fate intervened. The salesman, knowing full well that I was suffering from a full-blown case of aperture fever, steered me towards the scope that would give me the most bang for my buck: A used 6" reflector.



The telescope in question was a Meade 645 model produced from 1977 though 1980 or so, a wide-field, f/5 model with a 30" optical tube. It had a tracking motor and manual control worm gear on a German equatorial mount set on a massive pier. I didn't learn most of those details until much, much later. Three things penetrated my mind that day: 1) the tracking motor didn't work, 2) it was within my budget and 3) that 6" tube looked like a cannon. Aperture fever, indeed. So I bought it, with my dad spotting me $20 or so to cover the tax (a concept of which I struggled to grasp for years afterward as well, which my children today stumble over as well). The scope was mine.

This was a telescope designed for viewing deep-sky objects. Unfortunately, I never really figured that out. I observed the heck out of the moon, Jupiter, Saturn and Mars. I viewed Venus with disappointment, and searched in vain for Mercury. I looked at the Pledias fairly often, which is as close to DSO observing I ever got. I tried and failed to find the Andromeda galaxy and others. I saw the disappointing Halley's comet when it came through, low on the horizon. I got 2x and 3x Barlowes for my lenses, and even tried stacking Barlowe on Barlowe for ungodly magnification (didn't work, though). I got a T-ring and camera adapter, and hooked up my folks' Canon AE-1 to my scope. I ruined many, many rolls of film because I knew nothing about photography. Eventually I gave up because I couldn't afford to buy and process film that would invariably turn out over-exposed, under-exposed or blurred beyond recognition. I was woefully ignorant--I really, really wish I'd taken the time to learn what the setting circles on the mount did, because that would've made my DSO hunts a lot simpler--but what I lacked in understanding I made up for with enthusiasm. I had fun.

Eventually, I stopped hauling it out as much as I once did. My own ignorance was my biggest barrier, a hurdle that increased my frustration with observing. I wasn't seeing what I wanted to, but I never quite grasped the fault was with me. Eventually, I stopped getting it out at all, which is the fate of many telescopes. The last time I observed with it was when Comet Hale-Bopp swung through the skies in 1997. I packed up the scope and the Wife (we were still not that far removed from Newlywed status at that point) and drove out to Lake Belton in search of non-light-polluted skies. Afterwards, it pretty much sat undisturbed as a museum piece. Over the course of several moves, the scope got banged around and picked up a bunch of cosmetic blemishes. A few years ago, one of the acorn nuts securing the bolt attached to the secondary mirror spider snapped off. Benign neglect had taken its toll.

I'm not certain of the specifics, but sometime in the past year with my growing interest in photography and acquisition of a Canon XTi DSLR my interest in astronomy was rekindled. The impressive quality and flexibility of DSLRs in taking astrophotography is, no doubt, a major contributor to this interest. In any event, a switch flipped sometime in the past month and "Someday I'll get around to fixing up that old telescope" became "I'm fixing up that old telescope now." Work has commenced, sweat has been perspired and money has been burned through at an alarming rate. And you, gentle readers, will get to follow this restoration every step of the way.