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Telescope Design decisions

These are the design steps I'm working through. They're specific to my needs but should be easily modifiable.

Select a style (Done)

I've decided that the Dobsonian style of telescope appears to be the easiest to build on a ShopBot, and that building it using tubing trusses instead of a solid main tube is the construction method that will work best for me. Since I won't have a permanent place to set it up it will need to be portable, so one of the designs that can be dis-assembled makes the most sense.

Other than the specialized optical and mechanical parts like the lens and eyepiece tubes, the rest of the materials should be standard hardware store and lumber yard materials. 1/2" Baltic Birch Plywood is strong and stable, so that's the main construction material that I'll use.

Decide on size (Done)

Telescopes are defined by the size of the Primary mirror and the smallest Dobsonian telescope mirror available seem to be 5-6". The consensus seems to be that 8" is the smallest size that still makes a good telescope so that's the size I'm going to build. Others may want to build a larger scope...Mike Rawlings built a 12" telescope...but the basic design should be somewhat scalable.

Order components (Done)

The specifics of the optical parts must be known before the calculations and design of the various parts can be made. E-Scopes sells kits of all the specialty optical parts for several sizes of telescopes. Seems like it might be a good option to make the project more easily reproducable by others...all the size calculations should be the same..but I don't know enough to know if they are good quality. Will get opinions of people that know more than me (just about everyone!)...if anyone knows about these things please add info.

Decided to order the 8" f/8 kit from e-Scopes, with the upgrade kit. As soon as it arrives I'll work on the next step...sizing the parts.

Do design calculations

When the mirror is decided on, I'll use Newt software to define the overall dimensions.


  • e-Scopes sells kits of all the specialty components
  • Hands on Optics price list
  • 1/2" Baltic Birch Plywood
  • Aluminum tubing
  • Nuts and bolts
  • Misc supplies

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