George Ellery Hale, the astronomer who gave the world its largest telescope
four times, was an astrophysicist at heart. His specialty was the Sun. His
first really large telescope was the 40" Yerkes refractor. But he soon found
that this telescope fell short of the ideal instrument for solar research. 
The focal length was not sufficient to provide the large image which he
needed for his work. 

How do you obtain a longer focal length than that of the world's largest
telescope? Well, one way is to make the telescope stationary, and feed the
Sun's rays into it by means of rotating mirrors. By using an arrangement of
two mirrors (called a coelostat) the image could be kept in its proper
orientation as it moved across the sky. The heavy instrumentation could be
mounted on concrete piers, since it did not need to move. 

Hale used as his site a promising location atop Mt. Wilson, in southern
California. Using money from a grant by Miss Helen Snow, the mirrors were
produced by George Ritchey. The parts were carried to the top of the mountain
by mules, along a track which was at places only two feet wide! The telescope
was mounted on two heavy rails, 150 feet in length. The whole assembly was
protected by a long wooden building. Two main mirrors were provided, one with a focal length of 60 feet provided a solar image 7-inches across. The other, with a focal length of 143 feet, gave a 16-inch image. 

The Snow telescope soon proved to be successful beyond Hale's wildest dreams. He was soon able to demonstrate that sun spots were cooler than the
photosphere, and that they were the centers of vast cyclonic storms. Their
relationship to solar flares was apparent. 

The telescope produced a number of "firsts." It was the first truly
successful stationary telescope. It was the first telescope totally devoted
to the study of the Sun. And it was the first major instrument produced by
Ritchey, who later produced the optics for the 60" and 100" telescopes.