Below are photos of the historic telescopes of Lowell Observatory, Mars Hill,
, elevation 7,200 feet, from my visit in June 2013. The first photo is of the Clark Telescope, a 24” refractor, which Percival Lowell had built in 1896 so that he could study the “canals” on Mars. The lens was designed by Alvan Clark, the last lens he designed before he retired. Flagstaff, Arizona
|Clark 24" Refractor Telescope|
The Clark Telescope is now used only for public outreach. It is open for daytime tours and, if weather conditions allow, nighttime viewing until 10 PM every summer evening. The dome rotates on tires, obtained from the Ford Motor Company and installed in 1957, most including hubcaps, replacing the original worn out metal wheels.
|Inside of Clark Dome|
|Dome of Pluto Discovery Telescope|
|Pluto Discovery Telescope|
The tour guide told us that Clyde used the smaller telescope mounted below the astrograph to manually monitor that the astrograph was accurately tracking the stars during the one hour exposure, and manually nudged the astrograph if it was getting off track. Clyde had to endure cold temperatures because he captured the view of Pluto in January, the dome was unheated, and the elevation of Mars Hill is 7,200 feet.
|Pluto Discovery Plates|
The Lowell Observatory is a non-profit research institution, and it runs several other telescopes which are outside the
city limits, including the new $53 million, 4.3 meter Discovery Channel Telescope located 40 miles southeast of Flagstaff. Flagstaff
Even though the “canals” Lowell was observing were optical illusions and not signs of life of Mars and even though later evidence showed that no planet was disturbing the orbits of Neptune and Uranus,
made a substantial contribution to astronomy: he
- He was the first to build an observatory on a remote site to take advantage of optimal viewing, and now this is standard.
- His enthusiasm about life on Mars spurred public imagination and inspired science fiction writers.
- In 1912 - 1914 Vesto Slipher used a spectrograph attached to the Clark Telescope to determine the red shift in most galaxies which means the galaxies are moving away. Edwin Hubble used this information with his own research to conclude that the universe is expanding.
- Initial work in the discovery of Pluto.
- The Clark telescope was used to map the moon for the Apollo missions.
- His enthusiasm for public outreach continues. The visitor center at Mars Hill hosts over 80,000 visitors a years, and also hosts "Uncle Percy's" summer day camps for children from age 3 through 6th grade.