Mount Palomar Observatory
Published on Aug 3, 2007 at 12:31 pm.
2 Comments.
Filed under astronomy, observatories, telescopes, wonders.
Located atop Palomar Mountain in San Diego County, California, is the Palomar Observatory, operated by the California Institute of Technology.
Most famous among the instruments at Palomar Observatory is the 200-inch Hale Telescope, which was the largest telescope on Earth for close to three decades. However, the Hale Telescope is not the only instrument at Palomar. Palomar is also the home to a 60-inch reflector, a 48-inch Schmidt telescope, and an 18-inch Schmidt camera. The JPL Testbed Interferometer is also at Palomar, as well as the 4-inch Sleuth exoplanet search telescope.
The Palomar Observatory is the legacy of the great observatory builder George Ellery Hale. Hale was also responsible for the Yerkes Observatory, another in my list of wonders, as well as the Mount Wilson Observatory. After building Yerkes, Hale had gone to work securing resources for an even larger telescope in better sky conditions. That became the 60-inch telescope at Mount Wilson. Almost at once, Hale sought to build an even larger instrument, and eventually secured funding for the 100-inch Hooker Telescope, also at Mount Wilson. But, within just a few years, he yearned to build an even larger instrument. In 1928, Hale finally secured a Rockefeller grant for the construction of a telescope having a 200-inch diameter mirror. Such a huge telescope had never been even contemplated before. It would have four times the area of the Hooker telescope, then the largest in the world. But, Mount Wilson was getting full, so it would be difficult to locate such a large instrument there. Furthermore, the light pollution from nearby Los Angeles was making the skies at Mount Wilson far from ideal for such a world class instrument as a 200-inch telescope would become. So, a several year search for a better site for the observatory led to the selection of Palomar Mountain, about 90 miles southeast of Mount Wilson.
Fabrication of the 200-inch mirror was problematic, with several setbacks. However, the Pyrex mirror was finally cast and construction of the dome began in 1936. Though the mirror was cast, it still had to be figured into the correct shape, which involved removing nearly 10,000 pounds of glass. In the mean time, the 18-inch Schmidt telescope was completed and work began on the 48-inch Schmidt telescope. Hale never saw completion of his great vision, as he died in 1938. Soon afterwards, all work on both the 48-inch Schmidt and the great 200-inch telescope stopped as scientists and technicians were drawn into the war effort for World War II. Work did not resume until 1945. The mirror was finally installed, and the 200-inch telescope saw first light and was decated the Hale Telescope in 1948, ten years after Hale’s death. The 48-inch was also completed the same year. Additional fine polishing on the 200-inch mirror took another year or so. The 60-inch reflector was completed in 1970. The 200-inch Hale Telescope was remained the largest optical telescope on Earth for 27 years, when the BTA-6 telescope was built in the Soviet Union. However, even though the BTA-6 was slightly larger, the Hale Telescope continued to normally provide better images and was used for more science work. Adaptive optics on the 200-inch now allow it to reach resolutions previously unimagined. Even though there are now 17 telescopes larger than the Hale Telescope, it continues to remain a premier research facility and a wonder in astronomy.
Palomar Observatory, though, is not just the Hale Telescope. The other telescopes have been major players in astronomy. The 48-inch Schmidt telescope was used from 1950 to 1957 to photograph the sky seen from Palomar in the first Palomar Sky Survey. A second Palomar sky survey was conducted beginning in later (ending in 1999). This survey has been converted into a digital format.
-Astroprof
Images courtesy of Caltech Astronomy
A Ler…-- Rastos de Luz on August 6, 2007 at 12:43 pm: 1
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Astroprof’s Page » Palomar Spared? on October 25, 2007 at 6:10 pm: 2
[…] A while back, when I was writing my series on the Seven Wonders of Astronomy, I picked the Palomar Observatory as one of the wonders. Over the last week, as news poured out of southern California about the awful fires, I gradually became more concerned about the safety of the observatory. It was built in San Diego County, and that is where some of the worst fires were located. However, word was that the worst fires were well away from the observatory. But, that changed. One of the fires, the Poomacha fire, was actually in the vicinity of Palomar Mountain. They said several times that the observatory was not in immediate danger, and at one point Palomar Observatory was even listed as one of the evacuation sites, indicating that officials didn’t think that the fire was headed that way. And, now the wind has shifted, so the observatory is apparently safe for now. However, at this time it is closed, according to the observatory web site. I don’t know if that means simply not open to the public (but still doing research) or perhaps not even operating. But, at least the observatory seems to be out of danger. […]