She translated and simplified the works of Johannus Kepler into the common tongue. Kepler was an astronomer who determined a way to predict how the planets revolve about the Sun. Kepler's Laws of Planetary Motion are still used today. She made his rather esoteric work accessible to the scholars of that time. She even simplified his work by omitting the complicated use of the then new logrithms that Kepler used. For several centuries her translations were the only ones available to scholars. Her abilities in astronomy were so outstanding that she came to be called by the name of her book Urania Propitia, i.e., "she who is closest to the muse of astronomy".
But during her life she had to argue for her position as an astronomer. People thought her husband had done the work.