Author Archives: DaveTrott

Amateur Telescope Making Machinist (ATMM)


I used to get frustrated when I read about Amateur Telescope Making (ATM) projects that required machine tools since I did not have access to a machine shop. I still strongly support modest projects designed for the vast majority of telescope enthusiasts who do not have the inclination to buy a metal lathe nor the time to learn how to use it. It is great fun to test the limits of your skills with simple materials. I still enjoy making telescopes and parts from wood. It is a great challenge to make inexpensive telescopes that perform nearly as well as the best commercial products available. John Dobson inspired a lot of us!

Eventually I discovered that I needed metal to experiment with some novel concepts and designs.  As my ATM creations became more sophisticated I had to develop metalworking skills. It is very easy to be drawn away from telescopes. Home Machinists like to make their own tools and create wonderful mechanisms. It is an entire world! Though I have been seduced into a few such projects, I have steered away from all that and always return to my first love – telescopes.

I am working on a page devoted to my six inch folded refractor. I could not have built it without my small home machine shop. I have come to love my lathe and mill as much as my telescopes. My Southbend 10K lathe is one of my most prized possessions. It is an exquisitely beautiful example of perfect design and functionality.

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Why do I love Unitron Telescopes?

Some Unitrons


  • A perfect blend of functionality and beauty.
  • Exquisite craftsmanship
  • Many unique and quirky features.
  • Demonstrate superb attention to detail in every nut, bolt and knob.
  • Uncompromising standards of design and execution.
  • Deliver breathtaking performance.
  • Highly collectible and rare.
  • Small works of artistic and engineering perfection.

Another Youtube Tour of a Unitron scope at . Enjoy!

Unitron Video Tours

Unitron 145C

I have uploaded a couple of Unitron Video Tours. One is an overview of the 3 inch Unitron 145C. This scope is more properly called a “Frankentron” because it was assembled from various Unitron and shop-made components, like a sort of astronomical Frankenstein Monster. I included some nice closeup views of the beautiful setting circles. Please check it out at . The second tour is the 4 inch Unitron 160. There are more views of the spectacular Weight Driven Clock drive as well as a brief tour of the entire system. See this at There is also an amusing time-lapse of the assembly of this telescope at .

Unitron Telescope Weight Driven Clock Drive

I uploaded a video showing the operation of a classic Unitron Weight Driven Clock Drive. This 50 year old device allows a telescope to follow the very slow movement of stars and planets. The stellar motion is undetectable with the naked eye but in a telescope the movement is highly magnified so a tracking mechanism is very helpful. The device works strictly because of gravity, allowing the user to set up the telescope far from any source of electricity. It works much like a old fashioned Grandfather Clock. Like any old mechanical device, many find it fascinating to watch. Please visit to see the video.


The Double Arm Drive is still alive

The old Double Arm Drive invention is still alive and kicking after all these years. When I recently updated the links on my page, I found that a lot of people still build them despite the extremely short exposure times and stacked processing available with modern digital astrophotography. As a matter of fact, my interest was rekindled a couple of years ago when I bought a Canon T1i and I got out the original Type 3 Double Arm Mount I made back in the 1980’s just for fun.  I was able to produce some very nice shots with minimal post processing and no stacking at all.

Here is an example:Milkyway 50mm f3.5-10 rev4

This was taken with a modified Canon T1i using a 50mm lens at f 2.5 for 2 minutes 30 seconds mounted on a Double Arm Drive. You can see the Lagoon and Triffid nebulae as smallish red glows near the middle as well as the large dark nebula sometimes called “The Pipe” toward right center.