The planetarium is an inflatable black dome about 11 by 17 feet in diameter, powered by a projector that spits images out overhead.
Volunteer program coordinator Pat Monteith said education is the point of the program. "The whole idea is to be able to take it out to schools — we know for the past couple of years the schools haven't been able to do anything," she said.
The dome was funded by the City of Brockton's American Rescue Plan Act money.
Monteith said the program could bring not only astronomy, but also biology, earth science and cultural programs to the city's schools.
The dome got a cheerful reception from the library's youngest denizens on Saturday.
"I really liked it — I think I might want to go to space when I grow up," said one of the kids at the event.
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