When you picture an astronomer, you probably don't imagine a meek, devout Catholic nun. Yet in the early 20th century, four nuns took part in one of the greatest scientific undertakings of the era. Sisters Emilia Ponzoni, Regina Colombo, Concetta Finardi and Luigia Panceri were all recruited by the Vatican for the task of mapping and cataloguing over 400,000 stars. A stellar achievement!