I’m only capable of learning through mistakes, and lately I have been learning a lot.
To discuss my recent educational opportunities only in the field of amateur astronomy — there were plenty of other areas where my mistakes glared as bright as the sun — here are a few of the lessons hammered into me during February.
* Look out for frost.
As readers of Nightly News may remember from an unfortunate attempt to photograph the moon occulting the Pleiades, heavy winter frost can end a project fast. Methods are available to prevent frosting over, such as attaching a shield around the telescope to catch moisture.
* Take care not to strip the inside threads of setscrews.
Two weeks ago I tackled what I thought would be a challenging but not-impossible task, changing my telescope’s gears. My Meade LX200GPS 12-inch came equipped with nylon gears that have brass centers. (Newer models have solid brass gears.) I was concerned that eventually the nylon would wear out, and purchased a set of replacement stainless-steel gears, hex keys, tie strips, O-rings, a packet of grease and instructions. Called “Buck’s Gears Upgrade,” the kit is made by Peterson Engineering Corp. of Barrington, R.I.
Boldface lettering on the first page of the instructions warns, “While the proper installation of this kit will enhance telescope performance, PE Corp. assumes no liability for damage to your scope or injury to your person or other persons due to a lack of rudimentary mechanical ability, an inability to follow instructions or just plain common sense.”
Another of the printed cautions is, “The head on this little setscrew is easily stripped, so insure you’re using the correct size key (it fits very tightly) and be sure the key is fully inserted and pushed inward as you unscrew the setscrew.”
I replaced the declination gears, the gears that move the telescope up or down, without trouble. Pretty slick, I thought. I’ve puttered around on boats and cars, and this was far easier. Switching to the azimuth gears — which swing the telescope horizontally — I had no problem as I removed the mount’s base. A momentary mental warning came and went, the fleeting thought that the nylon gears were meshing well and showed no wear after years of work, and I could just leave well enough alone.
I took off the gear that had been fastened to the motor. All that remained was to remove the gear on the worm that engages the gear plate, replace both gears with the stainless steel ones, and get the cover on again.
I mangled the inner thread of the last remaining screw and it was stuck. Probably, in my overconfidence, I grabbed the wrong size hex key or used a worn-out one I’d had for years. The screw tightens onto a flat section of the worm’s axle and unless it’s out of the way, the gear can’t be removed. For hours afterward, I fought to get that gear off. I clipped through the nylon but the brass collar under it was too thick to cut. I tried to hammer new slits into the set screw so I could get it out; I used another hex wrench and a nail on this, breaking the wrench, without gripping the setscrew.
(The nylon gear, chewed up by my attempts to remove it, can be seen in the upper right background.)
Uncertain what to do next, I took the advice of Bruce Grim, a fellow Utah amateur astronomer, and posed a plea for help on an internet discussion group, one concerning my type of telescope. Great suggestions came in, mostly involving using a Dremel, which can auger out a ruined screw. But the best was this note, from Pete Peterson of Peterson Engineering Corp.:
“See paragraph 2 in the instructions: ‘Please do not hesitate to contact us should you have any question regarding the installation or the performance of your Buck’s Gears upgrade.’
“One possible reason for stripping the head of a small setscrew is the use of a cheap/weak hex wrench. A high quality genuine Allen hex key is provided in the upgrade kit for that reason.”
The note cited the caution against stripping the setscrew’s threads, and concluded:
“We stand behind our upgrades and we’ll be happy to remove it for you at no charge. Call me.
I called Peterson and he guided me through the task of detaching the worm and motor setup from the telescope mount. Then I took off the motor.
The most sensitive part was getting the connector for three wires off the computer board without damaging wires or board. Photographing the wires seemed the best way of making sure I got them back correctly.
I managed to extract the part and I mailed it to Peterson. A few days afterward it returned – without the old gear.
Putting on a new stainless steel gear, reattaching the motor and its new gear, and getting the part back into the telescope were not difficult. It was even easier to plug the wires back into the computer board.
* Keep an eye on the cat.
One of the last steps is to replace a small spring that provides just the right amount of tension for the worm. But the spring was gone.
We searched throughout the room. I thought of a variation of the nursery rhyme, “For want of a nail the shoe was lost.” Under the bed in my study, I plowed through the netherworld of dust bunnies, old computer parts, chargers, shoes and the occasional pistachio shell. My frustration level was climbing by the minute. I looked again: it wasn’t in the two envelopes where I kept screws.
I was about to give up when I casually reached under a sheaf of papers beside my desk. The papers sat on a dictionary so there was a small space between the floor and the papers. And in that small space was the spring.
As I was going through the final reassembly, Betsy started playing around the desk, stretching on the floor and reaching her paws under the sheaf of papers. Betsy, infamous for hiding toys behind stuff in the basement and under the stove, had struck again.
Reassembled, the telescope performed better than new, thanks to Buck’s Gears and the kindness of Pete.
* When you get a new cable, pay attention to how it works.
Today, Tuesday, the National Weather Service Inernet site surprised me by saying the night would be mostly clear at a favorite astronomy location. I quickly tested my equipment. Recently I’d bought a new cable for the battery so I would not have to hook the camera to my generator, whose output is erratic. But when I plugged the camera into the battery via cable, nothing happened. Deciding the battery had suddenly worn out, I canceled the trip.
I began to put away my gear. Only then did I notice the cable has an on/off switch. When I used the cable to connect the battery with the camera and switched on, it worked like a charm. But by then it was too late to pack up and drive to the desert before sunset, and I will not set up in the dark.