Going back to the late Nineteenth and early Twentieth Centuries, there has been a tradition of sidewalk astronomy. Sidewalk astronomy is really just what it sounds like: using a telescope on the sidewalk or street corner. Whether for free or for a small fee, these astronomers enticed the public to engage with outer space in an informal and exciting way.
More recently, John Dobson, an amateur astronomer, has brought sidewalk astronomy to the people of San Francisco. Beginning in the Nineteen Sixties, he has been engaging the public, even founding the organization of San Francisco Sidewalk Astronomers. Dobson also created a simple way for amateurs to build large telescopes, which are now known as Dobsonian telescopes:
The night is full of wondrous things—giant galaxies that look like pinwheels, clusters where stars swarm like bees, gauzy nebulae adrift in the Milky Way—but most of these lie beyond the capacity of the human eye. A large telescope—the larger the better to gather light—makes these objects visible. Says legendary comet-hunter David Levy, borrowing a thought from Bob Summerfield, co-director of Astronomy To Go, a traveling star lab: “Newton made telescopes for astronomers to observe the universe; John Dobson makes telescopes for the rest of us.”
Nearly a million people have looked through Dobson’s telescopes, which he constructs from castoff pieces of plywood and scraps of two-by-fours, cardboard centers of hose reels, chunks of cereal boxes and portholes from old ships. He puts his scopes on portable mounts that swivel sideways and up and down. “The Dobsonian Revolution was with just letting people look through the big telescopes, which was an extraordinary thing to do,” says Levy. “I think every advanced amateur astronomer in the world has at least one Dobson telescope.”