Amateur Telescope Making
Aluminum 10" truss Newtonian telescope During the summer of '99 I built this 10" truss tube Newtonian telescope. Actually, it was a rebuild from a traditional Newtonian I had built a year earlier using components originally from a Parks equatorial telescope.

The construction medium of this new scope is nearly all aluminum. I was inspired by the work of several people who've made metal telescopes. Gary Wolanski's web pages describe his 16" minimalist aluminum Dob project. Bruce Sayer's web pages offer several examples of beautiful instruments. Clive Milne's web pages graphically demonstrate his skill & proficiency with metal telescope making. My design goal was to create a lightweight telescope needing a minimum of space to transport and store. The scope has turned out to be a joy to use. Set up is quick & effortless. I haven't found it necessary yet to add a shroud to enclose the optics, although I probably will anyway.
"Ground Board"
Shown at right is the "ground board". All that matters here are the tripod arrangement of the feet, the teflon bearing pads directly over the feet, and the center pivot. The rest of the stuff you see here just holds those components together in their proper positions. The feet are hockey pucks that are superglued to the aluminum legs. Nylon nuts & bolts hold the teflon pads in place.
"Rocker Box" A pivot bolt through a nylon sleeve mates the "rocker box" to the "ground board". The 15" aluminum disk rides on those teflon pads shown above. I've previously used Ebony Star formica for this bearing surface, but here it's just the aluminum surface that glides on the teflon pads. It's got that "buttery smoothness" that's become the hallmark of the Dobsonian style Newtonian.

I was concerned with sidewall flexure and (probably) overdesigned the connection of the uprights to the disk using 1/4" aluminum angle stock. On the other hand, it's rock solid. Teflon pads for the altitude bearings top off the rocker box.
OTA in rocker box
Shown here is the "optical tube assembly" in position with the altitude bearing arc segments riding on the teflon pads of the "rocker box". The bearing arc segments are faced with Ebony Star formica in this case. Again, the motion is very smooth, with no "stiction". The overall weight is 33 pounds, 8 of which are the full-thickness 10" Parks mirror. The scope is a tad top heavy, so I'm using a counter-balancing spring (not shown) as proposed by Tom Krajci and his article in Sky & Telescope, November, 1999. It's an elegant solution to a problem brought on by the desire for a low pivot point for the altitude or elevation axis.

This was my first foray into working with metals as a construction medium. I've never been much good working with wood; I've always been too impatient, wanting to finish the job and get on with whatever I was building at the time.

Metal is less forgiving and therefore requires more care and attention to detail. So I learned to be patient and take the time required to do the job right. Measuring constantly and cutting and drilling precisely became the routine for doing the work. I spent a considerable amount of time just thinking about different solutions to the various problems presented in the construction. And still there were parts I made over 2 or 3 times.

The tools used for working the aluminum included a Craftsman router for rings and circles, a good quality mitre box with a metal-cutting saw, an electric drill (a drill press would have been very handy...), and a sabre saw. The aluminum stock was mostly 1/8" thick except for those 1/4" angles and the azimuth circle. Flat head hex socket bolts were the fasteners used and they were countersunk into the aluminum throughout the construction. And those red anodized aluminum truss tubes? Well, I just thought they were a nice touch...
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