Today, we look at some really big telescopes. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
The astronomer George Ellery
Hale was born in 1868 -- just after the Civil War.
As a 24-year-old professor at the University of
Chicago, he organized the Yerkes Observatory. There he built
the largest telescope ever to use a conventional
refractor lens. It was over three feet in diameter,
but it was also something of a dinosaur.
You see, astronomers gave up conventional lenses in
favor of focused mirrors after 1900. But Hale was
no dinosaur. By 1904 he'd convinced Andrew Carnegie
to give him $150,000 to set up the Mt. Wilson
Observatory in California. Hale was downright
greedy for high resolution and straightaway
developed the largest mirror telescope ever built
-- one five feet in
diameter.
At first he joyfully cried, "With this we'll record
... a billion stars!" But by 1918 he was back at
Carnegie's door for money to support a second
mirror, more than 8 feet in diameter.
He was now only fifty, but his health had begun to
fail him. He had to retreat from field work in
astronomy. But that didn't stop him from planning,
writing, and organizing. In 1916 he'd founded the
National Research Council, which was very important
in setting America's research agenda.
But one more telescope was on Hale's agenda -- a
really big one. Andrew Carnegie was dead by now,
but this time the Rockefellers gave $6,000,000 for
a third mirror -- one almost seventeen feet in
diameter -- the mirror that was to become the heart
of the Mt. Palomar Observatory, also in
California.
In 1934 the Corning Glass Company tried to make the
first rough casting of this 17-foot mirror. They
cooked a 50-foot lake of molten glass for six days
at 2700°F. When they poured it into the mold,
with the press watching, the inside of the mold
broke up. Nine months later they tried again and
succeeded. It took eight more months to cool it
down. Grinding it by hand to within a millionth of
an inch took years. The man who'd done this job on
the eight-foot mirror had ended in a mental
institution.
Hale died in 1938, and the Mt. Palomar telescope
was finally finished ten years later. And, until
the Russians made a larger one in 1986, it remained
the grandest optical telescope. Compare its
ninety-one inch focal length with the eight-inch
focal length of your long-distance zoom lens. It
finally took the new radio telescope to improve on
its resolution.
A person has to be moved by the unmatched vision,
nerve, and determination of this man. Just think:
over a 56-year period, from the age of 24 until ten
years after his death, George Ellery Hale gave us
the world's largest telescope not once, but four
times.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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