Measure by Measure, they touched heaven

Abstract

The measure of distances is a recurring theme in astrophysics. The interpretation of the light coming from a luminous object in the sky can be very different depending on the distance of the object. Two stars or galaxies may each have a different real brightness, although they may look similar. The correct measures were determined by women computers a century ago. Special mention is due to Williamina Fleming, who supervised an observatory for 30 years and worked on the first system to classify stars by spectrum. Antonia Maury helped locate the first double star and developed a new star classification system. Henrietta Leavitt determined a law to calculate stellar distances. The most famous of the Harvard computers was Annie Jump Cannon. An expert in photography, she catalogued over 350,000 stars and expanded the classification system used today, but it was Henrietta Leavitt who left an indelible mark by discovering a law for the determination of stellar distances. In the same period, Italian women computers began to collaborate in observatories, but their tracks are obfuscated.