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telescope maker. The French were more than happy
to bid him adieu.
Ritchey’s entire career in France had yielded only
a 0.5-meter Ritchey-Chrétien telescope mounted on
a wooden frame. The 40-inch telescope he designed
and built for the Naval Observatory, which went
into service in 1935, was Ritchey’s masterpiece,
nearly 25 years in the making. The only trouble was
that it had been built and installed on the observa-
tory grounds in Washington, D.C. Imagine the
Mona Lisa hanging on the wall of a barbershop.
The site just wasn’t very good.
A long legacy
Ritchey died in November 1945 at age 80. The
40-inch Naval Observatory telescope, now the
ancestor of all large modern research telescopes,
was moved in 1955 to a more optimal location near
Lowell Observatory in Flagstaff, Arizona. There,
the likes of John S. Hall and Arthur Hoag exploited
its superior resolving capability. The second large
Ritchey-Chrétien ref lector, the 84-inch telescope at
Kitt Peak National Observatory, was completed in
the spring of 1960, half a century after the first seed
of the idea took root in the fertile mind of its cre-
ator. From there, the Ritchey-Chrétien system swept
the world.
Ritchey was probably the greatest visionary tele-
scope maker of all time. In addition to the Ritchey-
Chrétien telescope, his ideas included cellular
mirrors, lightweight mirrors that respond rapidly to
temperature changes, internal dome temperature
control, thermal distortion-reducing telescope
mountings, and making rapid focus changes to opti-
mize f luctuating seeing conditions. These concepts
have now been used in nearly every large land-based
and space telescope since the completion of the
200-inch Hale ref lector — the last to use a parabolic
primary mirror — at Palomar Mountain in 1948.
The groundbreaking and historic Hubble Space
Telescope, as well as future supergiants like the
Thirty Meter Telescope in Hawaii, employ Ritchey-
Chrétien systems.
Had he been able to suppress his desire and
ambition, and fallen in line during the 100-inch
telescope’s development in the 1910s, Ritchey might
have had the opportunity to develop his “new
curves” system in smaller telescopes first, working
out the kinks along the way. In such a world, the
Hale Telescope could have been the first large
Ritchey-Chrétien telescope. This would have ben-
efited Hubble, Walter Baade, Allan Sandage, and
other cosmologists. But Ritchey’s insubordination
and Hale’s ignorance sealed the 200-inch’s fate
30 years before it was completed.
By contrast, Chrétien, who died in 1956 at age
77, was highly regarded during his lifetime and
rewarded handsomely for his contributions to the
field of optics. In addition to his Academy Award
and Prix Janssen medal, he received the Valz Prize
from the French Academy of Sciences. The
American Astronomical Society’s Chrétien
International Research Grant, which was created
in 1982 to award up to $20,000 each year in sup-
port of international observational astronomy,
was named in his honor.
Ritchey never lived to see his optical and instru-
ment designs “proclaim the glory of God,” as he
frequently wrote. Instead, his final years were spent
writing draft after draft of books about the astro-
nomical equipment he dreamed would one day
convey the true nature of the heavens. The fact that
he was never able to find a publisher for these vol-
umes was perhaps the final insult in a life dedi-
cated to designing the most advanced astronomical
equipment ever conceived. His legacy is written in
the incredible cosmological advancements his sig-
nature telescope design has allowed and will con-
tinue to generate well into the future.Ron Voller is a writer of science history based in New
York City. His forthcoming book, Companion Stars: The
Misfits Hubble and Humason Discover the Big Bang, is
due for publication in 2020.ABOVE: The Thirty
Meter Telescope
currently under
construction (shown
completed in this
artist’s concept)
will employ a Ritchey-
Chrétien design to
achieve the sharpest
images possible. TMT
INTERNATIONAL OBSERVATORYLEFT: The 200-inch
Hale Telescope,
housed at the Palomar
Observatory, was the
last major astronomical
workhorse telescope to
use the Cassegrain
design. CALTECH/PALOMAR
OBSERVATORY