Evening star. [volume], November 25, 1934, Page 10, Image 82

About Evening star. [volume] (Washington, D.C.) 1854-1972

Image provided by: Library of Congress, Washington, DC

                
if
New Eyes
βυ Solving
■ÏÏEG8Q
ι **
BY ROBERT D. POTTER.
MORE than ever the
North American con
tinent should become
the center of astro
nomical research
within the next few
years. Half a dozen great telescopes
are now completed, planned or
under contruction for observatories
in the United States or Canada.
When astronomers put on these
••stellar spectacles," speaking figura
tively. they expect to unravel more
mvKteries of the universe and the
stars scattered throughout it. They
anticipate a great age of astro
nomical fact-finding excelling the
discoveries made since the World
War, which began when Carnegie
Institute's great 100-inch reflector
- went into operation atop Mount
Wilson in California.
The 100-inch telescope of Mount
Wilson will soon have as companions
in probing the depths of space such.
instruments as the partially com
pleted 200-inch sky-searcher of the
California Institute of Technology,
being constructed in close co-opera
tion with Mount Wilson Observa
tory.
Tills huge apparatus, costing a
sizable fortune and requiring years
to complete, will be high on a
mountain peak of Southern Califor
nia where the air is clear and the
"seeing'' i.< good.
* At Ann Arbor, Mich., the next
few years will find completed a tele- ^0
scope with a light-gathering mirror
85 inches across. McDonald Ob
servatory in the Davis Mountains of Texas will
have a telescope with an 80-inch mirror. It
will be a co-operative venture of the University
Of Texas and the University of Chicago.
Τ TORONTO, Canada, Dunlap Obeervatory
of the University of Toronto will show ta
Visitors a huge telescope with a 72-inch mirror.
Remember, 72 inches is 6 feet; the height of
* taller-than-average man.
Famous Harvard College Observatory at Cam
bridge, Mass., which already owns fine astro
nomical instruments, will have a new telescope
with a 60-inch mirror, while in Washington, the
Nation's Capital, the United States Naval Ob
servatory is proudly showing to visitors these
days its new telescope of special design hav
ing a mirror 40 inches in diameter.
When the great Mount Wilson Observatory
Instrument was first turned toward the sky in
1919 there seemed little likelihood that its world
championship for size would soon be challenged.
Its 100-inch diameter mirror—and that Is 8|3
feet, or larger than the average room is high—
was the pre-war product of a famous French
optical works whose organization was completely
disrupted during the turmoil of the World War.
Many astronomers questioned—and they had
"" good reason for their doubts—whether the
years of optical skill which made the molding
of the great piece of glass possible could be
recaptured; at least until a new generation of
optical workers could be trained and organized.
In 1919 there was nq optical firm in the world
which would take an order for a piece of glass
the size of the Mount Wilson mirror. Perhaps
It is better to say that they might have taken
the order, but had little hope of accomplishing
the feat.
The 100-inch Mount Wilson reflecting tele
scope was and still is the champion, but it soon
yrill see its crown overthrown.
Second place for size in telescopes at present
Is held by Canada, whose telescope with a 72
inch mirror scans the sky at the Dominion
Astrophysical Observatory at Victoria, British
Columbia.
Third in rank of size, back in 1919, was Mount
Wilson's 60-inch instrument. Then came other
telescopes, 49 Inches, 40 inches and smaller, the
number of instruments increasing as the size
decreased. In all these telescopes the rays of
starlight were concentrated by the reflecting
concave mirrors, ground out with high precision.
But while a suitable mirror will focus light
and gather it—somewhat as a funnel gathers
rain drops and makes them come out of the
email end concentrated as a stream of water—a,
lens will do the same thing.
GREATEST of the lens telescopes, or re
fractors as astronomers call them, is the 40
inch instrument of the University of Chicago'·
Yerkes Observatory at Williams Bay. Wis. This
was one of the observatories which "caught" the
light from the star Arcturus and used the mi
nute amount of energy to turn on switches that
illuminated the Century of
Progress at its opening.
Almost as large—it haa
a lens 36 inches across—
is the great refractor of
the University of Cali
fornia's Lick Observatory
at Mount Hamilton, Calif.
Lens telescopes smaller in
size abound in America
and Europe.
On each side of the
United States work is go
ing forward that will re
tire the 100-inch Mount
Wilson telescope from the
"size" championship. In the
workshops of California In
stitute of Technology's new
astrophysical laboratories
construction work is pro
gressing on the framework
that will hold the new 200*
inch diameter mirror.
Across the continent at Corning. Ν. Y„ optical
workers are preparing to pour the great chunk
of glass which will form the mirror for this
new giant. This complex operation has already
been performed or.ce and a block of glass 17
feet In diameter has been removed from the
oven. The glass cast is half as wide as an
average city loti
The accident at the pouring of this great
mass of glass has led scientists to undertake the
operation a second time. It will be recalled
that pieces of light ceramic material, used to
produce depressions in the back of the glass
disc and so reduce its enormous weight, floated
to the surface and had to be "fished" out.
Optical makers believe the present solid chunk
of glass would make a good telescope mirror 200
inches in diameter. But from the experience
gained at the pouring last Spring they are cer
tain that a much better mirror can be built.
The present disc, therefore, will be held in
reserve as a spare and a new one made shortly.
Three years at least will elapse before this
new searcher of the sky will be placed on top of
Palomar Mountain in California and begin its
operation. It will be a co-operative project of
the California Institute of Technology and
Mount Wilson Observatory. Astronomers at
each institution will be able to use freely the
equipment of the other.
UIDING spirit of the manufacture of the
200-inch telescope is Dr. George Ellery
Hale, the founder and honorary director of the
Mount Wilson Observatory. Numerous Mount
Wilson astronomers are working upon Cali
fornia Institute's project.
Even if the 200-inch telescope were not well
under way the Mount Wilson instrument would
have to look to its laurels In a few years. The
gap in size between the 100-inch and the 72
inch telescope at Victoria is being closed rapidly.
Dr Heber D. Curtis, director of the University
ef Michigan Observatory at Ann Arbor, has
plans ready for a telescope with an 85-inch
mirror. The disc for this instrument has been
poured and is cooling. Completion of the in
strument will be delayed until financial condi
tions improve, for telescopes of this magnitude
cost money, and lots of it. It is hoped, however,
that construction can be started soon. A spe
cial feature of this Instrument is apparatus
designed for taking astronomical moving pic
tures.
Illustrative of the co-operation in astronomy
is the 80-inch telescope being built in Cleveland
for the McDonald Observatory of the University
of Texas.
This observatory will be situated on a peak
In the Davis Mountains of Texas as a branch
of the Yerkes Observatory of the University of
Chicago. The University of Texas will supply
the observatory buildings and the large instru
ment. The University of Chicago will supply
the operating personnel and much of the Inci
dental equipment.
In Canada the University of Toronto will
soon have in operation its Dunlap Observatory.
Chief of the instruments there will be a 72
inch reflector. The mounting is being made in
Newcastle. England, but the mirror will be made
at Coming.
Fifth of the new telescopes soon to go into
operation is the 61-inch instrument of Harvard
College Observatory, now essentially complete.
This apparatus is mounted at the new Oak
Continued on Thirteenth Page.
The largest piece of solid glass ever cast—the 200-inch disk for the California Insti
tute of Technology t telescope, cast at Corning, Ν. Y.
With completion of the last of tlïè^
half-dozen great telescopes planned
for Nofth American observatories,
y
ce looks forward to a great
of astronomical discovery
Tfw 72-inch reflecting telescope of the Dunlap Observatory of the
University of Toronto under construction in British icorksh<t[>s.