What is the importance of Harriet Tubman in the book, The Disordered Cosmos?

Harriet Tubman escaped from chattel slavery in the American South, making many return trips to lead others to freedom. Because Tubman used the North Star and constellations in order to navigate where she was going, Prescod-Weinstein presents her as an example of someone who could be seen as an astronomer when viewed through a framework that defines scientists based on their relationship with or study of the night sky, rather than whether they are paid by an academic institution.