John Dobson has a lot to say about the universe, including this: "We owe it to ourselves to notice it."

The 89-year-old astronomer, who sports a frosty white ponytail, is the engaging subject of "A Sidewalk Astronomer," a documentary that knows to sit back and listen as he expounds on a variety of subjects. He talks about the moon, the Vedanta (he was a monk before they expelled him for going AWOL) and God (whom he calls the Exterior Decorator) and whether time travel is possible, among other brain-bafflers.

Most nights you'll find Dobson on street corners, inviting passersby to look at the skies through his custom-built, cannon-sized telescope. While they peer through the lens, he gives them astounding facts in an accent that seems to hail equally from Ireland, England and, quite possibly, Kurt Vonnegut's planet of Tralfamadore. Dobson's mission, he says, is to hook ordinary people into contemplating the great beyond -- to make it their business instead of leaving it to the scientists. A co-founder of Sidewalk Astronomers, Dobson is best known for inventing and promoting the Dobsonian telescope mount, which allows telescopes to pivot and freeze in any conceivable position. Add to this, a discus-sized lens that brings the moon into sharp relief and suddenly the heavens are accessible to anybody. Unafraid of tackling the unfathomable, Dobson asks humankind to enjoy the same intellectual derring-do.

-- Desson Thomson