Using bowling balls, peach cans, roller-skate bearings, and Legos.
Easily within the skill-set of your average DIYer.
Popular Mechanics article on amateur telescopes
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Aside Where I went to school, we had the world's 7th largest refracting telescope. We couldn't see the girl's dorm 'cause the Home Ec building was in the way. But we could count the threads on the Venetian blind cords at a motel on the Interstate 17 miles away...
This was, of course, after some graduate students rigged the thing so it would depress below the horizon, a feature not included in the original design... Nasty grad students. Indeed!