Mount Wilson Telescope Celebrates 100 Years

Mount Wilson is celebrating its 100th year of being home to the telescope that provided the world with some of the most significant discoveries in astronomy.

17 photos
Mount Wilson Observatory
A "birthday" picture of the 100" dome at Mount Wilson Observatory.
Huntington Library
George Willis Ritchey was the Mount Wilson astronomer and optician responsible for making large reflecting telescopes the basic instrument of astronomical research.
Mount Wilson Observatory
The 100-inch telescope, driving machinery and dome machinery.
The Huntington Library/Carnegie Astronomy
Friday is the celebration of the "first light" centennial of the 100-inch Hooker Telescope at Mount Wilson Observatory. As part of George Ellery Hale's vision, in 1917 it was the pinnacle in technology for the new field of astrophysics and the world's largest until 1948. We are not celebrating this magnificent machine as much as the men and women who employed it to make ground-breaking advances in our understanding of our place in the universe.
The Huntington Library/Carnegie Astronomy
Edwin Hubble and Sir James Jeans at the 100-inch telescope North Cassegrain focus.
Mount Wilson Observatory
The old 100-inch telescope control console complete with right ascension and declination setting circle periscopes.
Huntington Library
The precision movement of the 100-inch telescope to track celestial objects across the sky was accomplished with a centrifugal governor. It was powered by gravity with falling weights attached by cable to a drum with a final output to a worm gear. Speed was regulated by changing the distance of the internal fly weights from the central pivot. Today, the observatory uses electrical servo motors to perform this function, but the governor is still intact.
Huntington Library
A closer look at the driving clock for the 100-inch telescope with a candlestick telephone for scale reference.
Mount Wilson Observatory
The worm gear for the 100-inch telescope was too large to transport as a single finished piece. The engineering solution was joining two transportable halves on site and cutting the gear so that it functioned properly. Below is a photo of Clement Jacomini cutting the many, many teeth on the 640-inch circumference.
Mount Wilson Observatory
Right ascension worm gear assembly used for positioning and tracking the 100-inch telescope.
Mount Wilson Observatory
An archived 1919 glass plate negative of the Moon through the 100-inch telescope.
Mount Wilson Observatory
Firmicus crater (56-kilometer diameter) as seen through the 100-inch telescope. Note the two peaks in the middle of the crater being hit by sunlight.
Norm Vargas
Globular Cluster M13 shot through the 60-inch telescope and 100mm eyepiece with a Canon T1i and 17 to 85mm 4 lens. Exposure is 20 seconds at f/4.
Mount Wilson Observatory
The negative glass plate of the M31 Andromeda taken on the 100-inch telescope.
Mount Wilson Observatory
The positive glass plate of the M31 Andromeda taken on the 100-inch telescope.
Matt Adame
Time exposure of Polaris over the 100-inch dome.
Dave Jurasevich
Aerial shot of the Observatory grounds.
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