Hans Crol (?-1591) was a German goldsmith and instrument maker who worked for Tycho Brahe between c.1584 and 1591.
Caroline Herschel (1750-1848) was an assistant to her brother William Herschel and a successful comet hunter in her own right. She was the first salaried female in the history of astronomy.
Margaret Flamsteed (c. 1670-1730) was wife and assistant to John Flamsteed, the first Astronomer Royal. Without her his greatest achievements would never have been published.