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 June 16, 1924, when Knut Lundmark and Sten Asklöf made a visit. Next to his name, Knut Emil Lundmark (1889-1958) wrote, “Ph.D., Upsala, Sweden.” He had completed his Ph.D. at Uppsala in 1920 and subsequently worked at the Lick and Mount Wilson observatoies. In 1929 he became director of the observatory at Lund University in Lund, Sweden. Lundmark’s scientific work was primarily concerned with galaxies.  He measured the distance to the Andromeda Galaxy in 1919 using  novae as standard candles. [Note: while certain types of supernovae function well as standard candles, novae in general vary in maximum brightness and do not serve the purpose well.] He measured a distance of about 650,000 ly (compared to the modern value of 2.5 million ly), which … Continue reading →