- The 200-inch reflecting mirror was made of Pyrex® by the Corning Glass Works of upstate New York (1934-1936)
- The mirror is designed to maintain its shape to a few millionths of an inch
- Grinding and polishing to a perfect paraboloid shape took place at the Caltech optics lab (1936-1947, with work suspended during World War II)
- Polishing removed 10,000 pounds of glass
- The housing dome is 135 feet tall and 137 feet in diameter
- The dome weighs approximately 1,000 tons, consisting of a plate steel exterior and aluminum panel interior
- Exterior and interior panels are separated by four feet, which allows ventilation
- The shutters that cover the dome’s opening weigh 125 tons each
- The dome swivels on two circular rails
- Astronomer Edwin Hubble took the first photographic exposure using the Hale Telescope in January 1949
Traffic and population density thinned quickly while traveling east, with four-lane roads surrendering to two. The landscape changed with every turn. Cactus and shrubs, boulders and crevices as well as houses tucked in among the slopes were visible from the road. Every once in a while, a patch of irrigated green demonstrated what could grow in this dry part of the country.
The curves of Highway 76 turned out to be just practice for what would lie ahead. The traffic sign designating Highway S6 to Palomar Mountain pointed toward a driving enthusiast’s dream. With the exception of one lone motorcyclist, the Impreza that I drove was alone going up that mountain road, and I was able to enjoy the curves and turns without interruption – one after another in seemingly unending succession.
Very few straight stretches of more than a few hundred yards interspersed the curves on the climb. Speed signs were consistently in the 25- to 35-miles-per-hour range. The views to one side of the road were of trees, boulders and walls of dirt, while sometimes nothing but sky could be seen on the other side.
If you like to drive and enjoy climbing ever-turning mountain roads, this Highway to the Stars is a must! Highway S6 leads to the Palomar Observatory from the southwest. Near the Observatory, S6 meets S7, which climbs the mountain from the eastern side. While not as wild, S7 has even greater views, particularly overlooking Lake Henshaw in the San Luis Rey River valley.
The Highway to the Stars ends in a park situated at the Palomar Observatory’s gates. A short walk up the pathway from the park takes you to the domed building that houses the Hale Telescope. The dome looks otherworldly, and I couldn’t help but think of 1950s science-fiction movies.
However, fiction plays no role in the contributions to astronomy made by the Hale Telescope and the other three instruments that make up the Palomar Observatory. They’ve helped to “map” the universe and discover some of its secrets.
Due to its large size, the Hale Telescope is the most impressive part of the Observatory. Its dome-topped enclosure is open to the public, with a viewing area overlooking the astronomers preparing for the night’s exploration of the universe. Exhibits help to explain the telescope’s operation and show some of the images it has captured.
The telescope was created by George Ellery Hale, who had supervised the building of the 60-inch telescope at Mount Wilson in 1908 and then the 100-inch telescope there in 1917. Two decades later, Hale secured a six-million-dollar grant for constructing an observatory with a 200-inch telescope. He selected the Palomar Mountain site after researching locations in Arizona, Texas, Hawaii and South America.