Dobsonian telescopes are popular with amateur astronomers for their portability and ease-of-construction, as well as their relatively large light-gathering capability. High school student Alex Patton decided to make his own, based on tutorials found on Stellafane.org as part of a directed study program at Chattahoochee High School in Georgia. He was allowed to use the engineering lab there for the project.
As he puts it, “I just like building things, and this seemed like a cool project. I figured that building my own telescope would be more rewarding and less expensive that buying one.” The ‘scope, according to Patton, cost him around $250, and would have retailed at around $400, so I’d call this a success, especially since he was able to do it as part of his education!
The telescope itself uses a 10 inch tube, normally used as a concrete mold for cement columns, as the main body. The inside of the tube as well as inside components of the telescope are blacked out to minimize any stray light, and the outside is painted a nice shade of blue. The tube supports are formed from wood and PVC, and a lazy Susan bearing is used on the bottom on top of a piece of plywood to easily traverse (adjust azimuth) across the sky.
One might not believe that a telescope made from cardboard tube could capture any detail from the sky, but, as seen in the moon photograph below, this isn’t the case. This was made possible by aligning the optics, a process called “collimation.” Per Patton’s writeup, “This involved orienting the secondary mirror so that it is centered over the primary, and adjusting the angles of both mirrors so that the reflected image goes straight into the eyepiece.”
For another take on the Dobsonian telescope, be sure to check out Make:’s instructions on how to construct your own!