Since its founding in 1891, many people have passed through the doors of the Vatican Observatory.  A quick perusal of our guestbook reveals several Names, including Popes, Nobel laureates, astronauts, actors, and saints. Today’s guestbook entry is from October 17, 1923, when Julien Péridier made a visit. Next to his name, Julien Péridier F.R.A.S. (1882-1967) wrote, “Ingénieur E.C.P. 16 Rue Cassette, Paris [apt] K.”  (E.C.P. is probably “École Centrale Paris,” where Péridier studied.) Péridier was an electrical engineer who worked primarily on public transportation systems in Paris. He was also an avid amateur astronomer. In 1933, he would found an observatory at Le Houga. After his death, he willed the instruments from the observatory and his library to the McDonald Observatory (University of Texas). In 1959 the Le Houga observatory was in a prime location to observe the occultation of the star Regulus by the planet Venus.  Using photoelectric photometry equipment, the team were able to produce a good light … Continue reading →