George Hale's Dream
The Palomar Observatory is part of Palomar Mountain socially, but it sits
above the community proper, both literally and figuratively. Owned and
operated by the California Institute of Technology, a privately endowed
educational and research institution located in Pasadena, California, the
Palomar Observatory is an institution with a world famous reputation. The
160 acre Observatory site is a self-contained home for the telescope staff and
visiting scientists. It operates year round, weather permitting, and "telescope time,"
at Palomar is a treasured commodity in
the astronomical community.
The principal telescopes in use at Palomar are the 18-inch Schmidt telescope,
the 48-inch Oschin Telescope, the 60-inch reflecting telescope and the mammoth
200-inch Hale Telescope. The famous 200-inch telescope was named for George Ellery Hale in recognition for his contributions to
astronomy, and his
dedicated efforts at shepherding the long and difficult process of constructing
the Palomar Observatory and the 200-inch telescope itself.
Hale was born in Chicago in 1869 and he died before the great telescope
bearing his name was completed. Hale made his first telescope at the age
of 19, inaugurating a lifetime fascination and professional dedication to
astronomy. During his career, he invented the spectroscope and the helioscope, contributing to the concept of the
stars as cosmic
laboratories.
The heart of the Hale Telescope is the huge 200-inch mirror that gathers
enough light to allow the telescope to look billions of light years
into space. When work
began on this mirror, at the Corning Glass Works in New York during the 1930's, no one was even
sure that a mirror of this size could be successfully cast. Special
glassmaking techniques and a custom formula for the mirror's pyrex disk
were required. The job was completed in 1934, and, after an eight month
cooling period, the 20-ton mirror was transported by rail to Cal Tech for final
grinding and polishing prior to its installation at the Palomar
Observatory. These preparations were almost complete when they were
interrupted by World War II, and it was not until 1947 that the 200-inch mirror
was finally installed in the giant white dome of the Hale Telescope.
For many years the Hale Telescope was the largest optical telescope in the
world, and it has racked up some impressive scientific achievements over the
years. In 1952, astronomers used the Hale Telescope to view distant
galaxies and reveal that our universe was both older and larger that we had
believed. In 1963, the mystery of "radio stars" was solved using
the Hale Telescope, and the celestial objects known as quasars were first
described by Maarten Schmidt. Over the years the research value of the Palomar telescopes
has been eclipsed somewhat by
development of other optical scopes with larger mirrors and, most significantly, the
Hubble space telescope. That said, observing time on the Palomar telescopes is still a precious commodity and they are used
for a variety of research studies on every clear night.
A typical night's observing at Palomar will likely include a variety of
research plans. The study of
asteroids and comets, so called "near-space" objects plays an
increasingly large role at Palomar. The Shoemaker-Levy comet that crashed spectacularly
into Jupiter in 1994 was originally discovered at Palomar using the 18-inch
Schmidt. In another area, the 48-inch Oschin Telescope operates like a huge camera, capturing
incredibly detailed images on 14 inch glass plates. It is currently
involved in the creation of an atlas of the entire northern sky that will
provide a basic resource for astronomers world wide.
The usefulness of the 200-inch Hale telescope has improved dramatically in
recent years through the installation of sophisticated CCD sensors that are hundreds of times
more sensitive to the faint light from distant celestial objects than the
photographic plates the telescope was originally designed for. Other sensors
and "adaptive optics" are used to detect infrared light allowing researchers to "see" outside the
visible spectrum and correct for atmospheric distortions. These improvements have helped keep the Palomar Observatory an important and
valued research tool despite the encroaching light pollution from the city of
San Diego spreading along the base of Palomar Mountain.
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1 Palomar Observatory Info: http://www.astro.caltech.edu/observatories/palomar/history/
2 Comet Shoemaker - Levy 9:
http://www.seds.org/sl9/sl9.html
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