by Jay Reynolds Freeman
My only power tool for this project was an electric drill. (My seamstress friend used a sewing machine.) Several special tools and jigs helped. I bought a thin saw with fine teeth set to cut on the "pull" stroke. It derives from Japanese carpentry, and was a joy to use. I could split a pencil line when sawing, and my cuts required only a few finish strokes with sandpaper, and I am by no means an experienced carpenter. I also used a drawknife -- a very old tool for shaping wood -- and a good set of wood chisels. I kept chisels and drawknife razor sharp, and took great care that they cut only wood, not flesh.
I had a simple drill stand so I could use my electric drill as a drill press -- that was extremely useful. Also useful was a good hand miter-box saw assembly -- a fancy metal unit, with clamps and guides, adjustable to many angles, with a high-quality backsaw.
I had a variety of store-bought clamps for gluing. The project would not have succeeded without them. I built several special jigs. Useful ones included some simple wooden "V"s, to support a 90-degree angle edge down, so I could weigh down a glued joint while the glue dried, and a strip of metal with holes pre-drilled at the design separation of the fastener holes in opposite ends of my truss poles.
Except for the truss poles, the telescope packs into roughly a 14-inch (36 cm) cube for transport. With side bearings removed, the box nests into the rocker, and the octagon fits into the top of the box. I found a Rubbermaid refrigerator container about 11 inches (33 cm) diameter and 4 inches (10 cm) deep, just right to hold the primary with plenty of padding. It also fits into the box, under the octagon. There is lots more room in the box for small parts, accessories, and tools, or for clothing and non-telescope stuff, either as padding or to distribute weight more evenly among pieces of luggage. The ground board and side bearings fit around the rocker, to make up the rest of the cube.
Even though all the parts mentioned do indeed fit into the cube, I actually packed for traveling by putting as many small, heavy parts as possible into my other piece of luggage, and filling gaps in the telescope case with clothing and other light items. All the fasteners used for motel-room assembly traveled this way. Without doing so, the case would have been very heavy and awkward to handle.
The container I bought from Atlas Cases has an interior that is approximately an 18-inch (46 cm) cube. It came with two inches of foam lining, which I trimmed with a bread knife for a snug fit. It has handles and latches; I drilled holes for a long, bicycle-lock style padlock, which seems enough to deter casual pilferage. Anyone who steals the entire case can take it somewhere private and open it with power tools, so a fancier lock won't help. But the case is stout enough that I can dance on it.
I added threaded inserts to the case bottom, for simple rubber feet, sized to sit on Celestron vibration-damping support pads. Thus I can sit the telescope atop the case when I am working near the horizon, to raise the eyepiece from a rather awkward 40 cm to nearly a meter. That's steady enough for deep-sky work at 106x -- the magnification I found myself using most often -- and surprisingly so, since the case flexes easily. The explanation seems to be that the light finger pressure required to steer a well-balanced Dobson isn't enought to distort the case noticeably.
The vibration damping-pads worked well. I noticed no jiggles when I was observing. Wind-induced vibration is sometimes a problem with telescopes, but when sitting on its case, the 10-inch showed no wind-induced vibration at the eyepiece, even at wind speeds sufficiently high that I had to keep a hand on the telescope to keep it from turning like a weather vane.
When I am putting something together away from home base, I can count on finding a crack in the earth that goes clear to the antipodes, because I am certain to drop into it some fastener the whole project depends on. So my rule about spare small parts is, take 50 percent extra, but never less than two. If the gadget needs one 1/4-20 by two-inch Allen head machine screw, I take that one, plus two spares. If it needs six, I take nine. And so on.
I bring enough tools to get by if I lose one. A "Leatherman" or similar pocket gizmo is a handy backup, but do put it in checked baggage to keep airline security happy. I take stuff like Epoxy and grease, for repairs and maintenance. I have a spare truss pole. And don't forget duct tape, so if the universe breaks down, you can fix it, too.
I lucked out. The 10-inch Dobson came up smoothly. Everything fit together. The pieces all fit in the case. The focal point was where I intended. The balance was a little tail-heavy with the solid truss poles, but the extra weight of the joints for the cut poles put it dead on. I worked hard to get the telescope ready weeks before traveling, so there would be time for modifications, but none were required.
Yet I learned a lot from the use I had of the telescope, before my first trip. Some of it was relearning the habits of Newtonians: I have made thousands of observations with them, but it has been a long time since I used one extensively. Some of it was familiarization with this particular telescope -- it went together a lot quicker the second time than the first. And some things were useful new ideas, suggested by experience -- the bit about putting feet and vibration dampers under the case, to use as a stand for working near the horizon, was one such.
Anyhow, after five nights' experience and over a hundred objects logged, I was ready for my first trip south -- to Hawaii.
Reference:
Kriege, David, and Richard Berry. The Dobsonian Telescope: A Practical Manual for Building Large Aperture Telescopes, Willmann-Bell, 1997.