Hale telescope construction. Skeleton tube of the 60 inch Hale telescope being carried up to the Mount Wilson Observatory in the San Gabriel Mountains, California, USA, on a mule train. The Mount Wilson Solar Observatory, as it was then known, was founded in 1904 by George Ellery Hale. The telescope was operational by 1908 and at the time was the largest in the world. The Mount Wilson Observatory became the world's foremost astronomical research facility, allowing Hale to found the new field of astrophysics.