Advantages of making at least part of your own telescope


1.    Putting in the ‘sweat equity’ guarantees that it won’t be a fly-by-night hobby you spend money on and then forget about later; it gently forces you to learn a lot more about optics, seeing, and astronomy.

2.    You can make a much better telescope than you can buy for anywhere near the same amount of money. No kidding!

3.    You can tweak, or improve, an already-existing telescope to eliminate problems or improve performance. (For example - you can eliminate or reduce internal reflections on bright objects; you can install a better focuser or finder; you can improve how the telescope moves.)

4.    There is no easier telescope on earth to use than a home-made Dobsonian-mounted Newtonian reflector; and its images are much brighter and crisper than any catadioptric telescope of its size.  (For example: there is no lengthy polar alignment; setting up the telescope takes seconds, not minutes or hours.)

5.    The mount can be absolutely rock-steady, unlike the unsteady German equatorial tripod-mounted telescopes most beginners buy. If you hit the side of a Dob very hard with your hand, the telescope will shake for a second or two at most. However, if you so much as touch a standard 'beginner scope' like a German equatorial mounted small refractor, it is likely to vibrate for about 7 to 10 seconds, during which time you can't see anything. When you push a Dob a bit to the right or down a bit to follow a planet, then the scope will stay right there where you pushed it, with no backlash or wobbling. That is not the case with your typical cheap, wobbly commercial mount! Really steady equatorial mounts are very, very expensive (many hundreds of dollars at least.)

6.    If you choose to make the main mirror yourself, you will have made, with your bare hands and no power tools, the most accurate and precise large surface that humans can possibly make. The surface can easily be accurate to better than 1/10 of a wavelength of green light, over the entire surface. No microchip is so accurate for so large a surface.

7.    Quality control at major telescope manufacturing companies is ‘iffy’. Some commercial mirrors are good, and some are very poor. It costs them too much to make the optics as good as you can do on your own as a hobby, because of the amount of hand labor required for perfection.


If you think you might like to make your own telescope optics, then check out the National Capital Astronomers’ mirror-making workshop, held every Friday evening from 6:30 to 9:30 PM (except for holidays and major snowstorms) in the basement woodshop at the Chevy Chase Community Center at McKinley Street and Connecticut Avenue, NW, in Washington, DC, near Chevy Chase Circle. There is usually parking in the back. All of the materials and instruction for a 6” mirror cost $70.00, not including aluminizing the mirror. We can also test (free) or re-aluminize (small fee) your current mirror. Contact Guy Brandenburg at gfbranden@earthlink.net or 202-262-4274 for more details.

last updated on July 26, 2003