Photographic plate that led to the discovery of Comet 67P. Plate was taken/developed by Svetlana Gerasimenko, co-discoverer with Klim Churyumov of Comet 67P/Churyumov-Gerasimenko. Inset picture is Gerasimenko (1975). Image courtesy for both pictures: Klim Churyumov
A tribute to American astronomer Henrietta Swan Leavitt (July 4, 1868 – December 12, 1921). While working at Harvard College Observatory, Leavitt discovered the period-luminosity relationship for Cepheids.