The Snow Horizontal Telescope

 solar telescope  Add category

Originally donated to Yerkes Observatory in 1903 by Miss Helen Snow of Chicago. She put up 10,000 dollars for it's construction, with the provision that Professor Hale name the instrumentin honor of her father, George Washington Snow.
A "horizontal" solar telescope, it was moved out here to California in 1904 for the superior seeing conditions and it became the first permanent instrument on Mount Wilson. Now a mile above sea level, it produced the best solar images and the best spectrographic data of it's time. The original "building" was a rustic affair covered with canvas. This was deemed a fire hazard and replaced in 1911 with a corregated metal shell.
The black and white photo, circa 1912, shows the louvered arrangment of the aluminum siding, much like an old style industrial cooling tower. The idea was to allow plenty of air to circulate throughout the shed, thereby avoiding heat build up.
The sun's ligh is reflected from a 30 inch flat coelostst mirror to another 30 inch flat, which sends the beam hotizontally 100 feet to the back of the building. There a 24 inch concave mirror (f/30) focuses the solar image on the diffraction slit of the spectrograph. At prime focus the sun's image is 16cm across.
Original there was an alternate main mirror available, with a focal length of 143 feet. It produced, at the focal plane, a solar image 16 inches in diameter.
No longer used for basic research, the Snow Telescope remains in good repair and is still used as an intructional tool.

View of the 60 foot telescope tower adjacient to the Snow Telescope, as seen from the top of the 150 foot telecope, photo by Colleen Gino.