Making Telescopes
Takes a Lot of Grit
But Little Money
---
An Ex-Monk Can Show You
How to Build a Good One;
Elbow Grease and Scraps
By Joan Indiana Rigdon01/13/1997
The Wall Street Journal
Page A1
(Copyright (c) 1997, Dow Jones & Company, Inc.)SAN FRANCISCO -- John Dobson is known as a stickler for detail.
At the moment, he is focused on the fine points of grinding a telescope
mirror by hand. "The curve has to be perfect to within one
one-thousandth of the thickness of Saran Wrap," he instructs a roomful of
students here at the Randall Museum."What if we're way off?" a voice pipes up.
"What!" the wiry, 81-year-old Mr. Dobson shrieks, his white ponytail
flipping behind him as he searches the class for the upstart. "We don't
give you instructions to get you way off! We've made a few thousand of
these," he yells. "We think we know what we're doing."And he does. Mr. Dobson, a former monk and atomic-bomb builder, is
the Johnny Appleseed of telescopes. For the past half century, he has
traveled the world instructing thousands of novices in the fine points of
producing superpowerful optical instruments on the cheap. Many of the
6,500 Americans who grind their own telescope mirrors each year use
Mr. Dobson's methods."It really is kind of a cult," says John R. Sanford, president of the Orange
County Astronomers, whose 600 members include dozens of Mr.
Dobson's disciples.Mr. Dobson's telescopes, called "Dobsonians" by those who love them,
currently cost only about $250 to build. His students, who pay $60 for
10 class sessions, turn out 10-inch to 24-inch mirrors on 6-foot-long
mounts that resemble medieval cannons. Mr. Dobson likens
store-bought, motor-driven telescopes to drunk drivers -- often
meandering off target and weaving across the sky when viewers try to
focus on a fixed object. "Our telescopes neither drink nor drive," he
boasts. Nor do they consume electricity. "They run on yogurt and eggs,"
he says. "We eat the yogurt and eggs, and then we push them around."Dobsonians, says San Luis Obispo, Calif., optical engineer Gerard
Pardeilhan "are fantastic." The best match professional telescopes costing
thousands of dollars, says Mr. Pardeilhan, himself a Dobson student as
well as the creator of optical cameras for the world's largest telescopes,
including the 400-inch Keck telescope atop Mauna Kea in Hawaii.Mr. Dobson's secret is simplicity. Rule No. 1: Ignore books on how to
build a telescope. "They are written to encourage a few dozen and
discourage a few thousand," he says. Instead, he draws on his own
experience.Dobsonians are usually put together from scraps. Mr. Dobson's first
several hundred students made theirs from old portholes and the bottoms
of glass jugs. (Most now use factory-made glass.) Mounts are plywood
and cardboard tubes used for forming concrete columns. Eyepieces come
from old binoculars. Phonograph turntables help the giant telescopes to
swivel on their bases. Mr. Dobson suggests using old shower caps to
keep dust off mirrors.Mr. Dobson urges elbow grease for the most daunting part of telescope
making -- grinding the mirror. Most professionals use expensive machines
that shape mirror curves. Mr. Dobson's students sprinkle on grit and
water and use another piece of glass to grind by hand. After a few
up-and-down strokes on each side, they turn mirror and glass and grind
away some more.The constant grinding and turning produces a near-perfect curve in about
four hours for a 10-inch mirror, followed by several more hours of fine
grinding and polishing, and a coat of aluminum to make the mirror reflect.
Mr. Dobson rallies his charges with aphorisms like "Rough grinding is a
cave man's job. Eat well, sleep well and work like hell."Mr. Dobson has been making telescopes since 1944, a year after he
graduated from the University of California, Berkeley, with a bachelor's
degree in chemistry and math. He quit his job on the Manhattan Project,
where he helped develop the atom bomb by testing the chemical effects
of shooting superfast electrons at targets, and joined the Vedanta Society,
a group founded on religion and philosophy from India.Behind the walls of Vedanta monasteries in San Francisco and
Sacramento, Mr. Dobson began ruminating on telescopes, wondering
whether a glimpse of the glories of the solar system might spur people to
question the origins of the universe? A fellow monk borrowed a book on
grinding telescope mirrors from the public library and Mr. Dobson was
hooked.Mr. Dobson's first telescope was a 2-incher, with a lens he found in a
thrift shop. He spent the next 13 years building bigger, more elegant
contraptions, culminating in his first 12-incher, which he built in several
weeks in 1957.Mr. Dobson's heavenly preoccupation alarmed the monastery's head
swami, who felt it could disrupt discipline. So Mr. Dobson went
underground, smuggling in his telescope glass in boxes of fertilizer, which
fit with his job as monastery gardener. At night, he would sneak out,
sometimes scaling the fence, to work on his telescopes in a neighbor's
backyard. He lent his telescopes to neighborhood children.The monks found him out and, after he disregarded their warnings,
kicked Mr. Dobson out in 1967. He moved into a friend's apartment in
San Francisco, sleeping on the floor and teaching his skill to others. Soon
he was producing 16- and 20-inch telescopes -- giants at the time -- and
carting them to Grand Canyon and other national parks across the West,
offering tourists a glimpse of the heavens.To make ends meet, Mr. Dobson tapped an unusual trove: four tons of
portholes he bought at auction for $1,000 in 1969. He sold them to
students over the next 20 years.Telescopes have remained the focus of Mr. Dobson's life. Although he
has a world-wide reputation as a telescope maker and is asked to speak
at science and telescope conferences, he still lives simply, sharing a
ground-floor apartment with three roommates near downtown San
Francisco. He teaches cosmology at a local yoga center.On clear nights he works the sidewalks here, showing off the heavens to
passersby. One Sunday, two students line up on a downtown sidewalk
while Mr. Dobson checks the curves on their newly made telescope
mirrors. Both pass, but when one student, electrical contractor Larry
Maas, asks to polish his mirror one more time, Mr. Dobson snaps:
"There's a limit to how long the human life span goes. You can spend 40
years polishing, and I'm not in favor of that."Mr. Dobson estimates he has helped students build thousands of
telescopes. He has made several dozen himself, stashing many with
friends throughout California. But his first 12-incher has disappeared.
Former students say Vedanta monks threw it into San Francisco Bay.Mr. Dobson says he has heard as much but prefers not to discuss it, since
he has so many others. "How would I miss it?" he says. "I've got more
telescopes now than I've got places to put them."
-30-