Maria Mitchell, born on Nantucket in 1818, was a navigator, librarian, and astronomer who discovered a comet through a telescope in 1847 and subsequently became the first professional female astronomer in the United States. The Maria Mitchell Association honors her legacy with two observatories, a natural science museum, and an aquarium. Both observatories are important research centers. You can take a guided tour of Vestal Street Observatory on weekdays from June to September, and the ticket also allows you into the museum, aquarium, and Mitchell's house. Loines Observatory, on the way out of town across from the cemetery, runs public stargazing and other events. But even if you don't get a chance to visit the observatory, stargazing is inevitable on this island: Just look up at night to enjoy a black sky sparkling with starlight.