Before Neil deGrasse Tyson, before Carl Sagan, before Edwin Hubble, there was Maria Mitchell.

She was an international celebrity in her day, celebrated by — among others — the King of Denmark. A World War II Liberty ship was named after her, as is a crater on the moon. And yet, today, her story remains little told. It's a story that begins on the island of Nantucket.

"Maria Mitchell was and is America’s first woman Astronomer. Everyone knew who she was," said Jascin Finger, deputy director at the Maria Mitchell Association on Nantucket. "Maria actually said her first love was mathematics. But it was more sympathy for her father that led her to astronomy."

In the mid 19th century, on Nantucket, where they lived, Mitchell’s father William Mitchell was, among other things, an astronomer. On clear nights, even terribly cold ones, he’d gaze into the skies, observing, making calculations, with young Maria by his side.

"They very much became partners," Finger said. "He’s a mentor to his daughter, as well as a teacher."

By the age of 12, she was already showing astonishing promise.

"She and her father viewed a solar eclipse from their home at 1 Vestal Street and Maria clocked the seconds of the eclipse and they were then able to determine the longitude of the house," Finger said.

And so Maria worked — and studied — encouraged not just by her father, but also by her unique surroundings. In her Quaker household, both girls and boys were educated, unusual for the time. And Nantucket in the 1800s, was unlike anywhere else in America.

"Because of whaling taking so many — not all — but many of the men away to sea for long periods of time, because of the Quaker influence, and then also simply because of the isolation, women on Nantucket had a lot of opportunities that women elsewhere in America didn’t have," Finger said.

And so by age 29, like many Nantucket women, Mitchell was working — outside the home. Her days were spent as the librarian at the [Nantucket] Athenaeum. At night, telescope in hand, from the rooftops she’d “sweep the heavens.”

"Late night observations, and then also doing all of the calculations that she needed to complete for those observations, both on her own and with her father," Finger said.

One late night, Oct. 1, 1847, she spotted something new. She watched, calculated, and charted. There was no mistake: Maria Mitchell had discovered a comet.

"It showed people that she really did know what she was doing and could do the math that was required to prove that she could actually calculate the path of this orbit," Finger said.

The comet was dubbed “Miss Mitchell’s Comet.” Her work earned her a gold medal from the king of Denmark — himself an astronomy enthusiast — and international acclaim.

"People start coming to Nantucket just to look at her," Finger said. "She said at one point that she felt like an animal in a cage because people would come not to see the Athenaeum but to see quote unquote the lady astronomer."

Finger says the discovery opened doors for Mitchell, who in turn, opened them for other women. She became one of the first women to work for the federal government; the first woman elected to the American Philosophical Society; America’s first female professor of astronomy; and the first person — man or woman — hired to teach at Vassar College.

"I think having her at Vassar assured parents, when women’s colleges were still a new thing, that if America’s first women astronomer teaches at Vassar that must be a good place to send my daughter.

Finger says it’s important to note that despite the unique advantages Maria enjoyed as a woman on Nantucket, she still had no formal schooling beyond the age of 16. Largely self-taught, Maria would become a steady — and influential — voice for women’s education.

"Maria once said to her students 'we are women studying together,’'" Finger said. "She didn’t believe in lecturing. She believed in her students working with her side by side as partners, just as she had with her father. And I think that’s something important to realize how much she has influenced learning."

Maria Mitchell, America’s first woman astronomer, a trailblazer in every sense of the word, launched onto the international stage when she discovered “Miss Mitchell’s Comet” from her Nantucket rooftop, 168 years ago this week.

An earlier version erroneously referred to the King of Norway, rather than the King of Denmark.

If you have a tale of forgotten Massachusetts history, let Edgar know. Email him at curiosity-desk-at-wgbh-dot-org.