The Clark Telescope, a national treasure and site of notable discoveries such as the dwarf planet Pluto, is closing Jan. 1 after 117 years of constant use for a much-needed facelift, officials at Lowell Observatory said recently. The Clark’s dome is made of local Ponderosa pine wood and was constructed in Flagstaff. The dome, weighing eight tons (7300 kg), sits on 24 replica 1954 Ford pickup tires and is rotated by three electric motors. Courtesy of Wikimedia Commons. The instrument, which saw first light on July 23, 1896, will be closed for more than a year as engineers and technicians remove components and repair or replace poorly operating parts. The Clark was built by one of the preeminent telescope makers of the time, the Alvan Clark & Sons firm of Cambridgeport, Mass. “Mr. Clark himself ground the two 24-in. (61-cm) diameter lenses; this set of optics is still one of the finest made in this epoch, and is especially effective for the study and observation of planets,” the observatory says on its website. “The telescope tube is 32 ft (10 m) in length, made of rolled steel, and with the other moving parts weighs six tons (5400 kg). Despite the weight, this telescope is so well balanced that it is easily moved by hand.” Percival Lowell, who founded the Lowell Observatory in 1894, initially used the 24-in. Alvan Clark refractor to study Mars in support of his controversial theories about life on that planet. Significant research with the Clark included Vesto M. Slipher’s discovery of the first evidence of the expanding nature of the universe in 1912-1914, the confirmation of Pluto’s discovery in 1930 (made by Clyde Tombaugh with another telescope at Lowell Observatory), and creation of lunar maps in the 1960s in support of NASA’s Apollo program. Although it is no longer used for research, the Clark is still used as part of the observatory’s Mars Tour and is used for nighttime viewing. Actor Leonard Nimoy visiting the Clark Telescope with Carolyn Shoemaker during a 1998 film shoot. Courtesy of the Lowell Observatory. “The Clark Telescope is a national treasure and is Lowell Observatory’s first research telescope,” said Lowell director Jeff Hall. “Last year, we celebrated first light of our newest eye on the sky, the Discovery Channel Telescope, which will carry us through several more decades of astronomical discoveries, as the Clark did in the early days of Lowell. That makes it an appropriate time to look back and ensure that this telescope that started it all — a lovely old refractor in the wooden dome overlooking Flagstaff — is restored and maintained for the hundreds of thousands of visitors to Mars Hill who will look through it in the future.” The renovation project is supported in large part by major donations from the Toomey Foundation for the Natural Sciences and by the late Joseph N. Orr. A successful crowd-sourcing effort also raised significant support, and the observatory is still accepting donations to complete the work. For more information, visit: www.lowell.edu