Exploration of the Moon invention of the telescope, an increasing number of people began to recognise the Moon as a sphere, though many believed that it was "perfectly smooth". In 1609, Galileo Galilei drew one of the first telescopic drawings of the Moon in his book and noted that it was not smooth but had mountains and craters. Later in the 17th century, Giovanni Battista Riccioli and Francesco Maria Grimaldi drew a map of the Moon and gave many craters the names they still have today. On maps, the dark parts of the Moon's surface were called "maria" (singular "mare") or seas, and the
A. E. Douglass and visible cusps on Venus. Craters on the Moon and Mars are named in his honor. After a 5-year hiatus from astronomy, Douglass left Flagstaff, Arizona in 1906 and accepted a position as Assistant Professor of Physics and Geography at the University of Arizona in Tucson, Arizona. Almost immediately upon his arrival in Tucson, Douglass re-established his astronomical research programs using an 8-inch refracting telescope on loan from the Harvard College Observatory and actively began to pursue funding to construct a large research-class telescope in Tucson. Over the next 10 years Douglass was unable to secure funding from the University