Science Builds Greatest Telescope (Sep, 1938)
Science Builds Greatest Telescope
Monster 200-inch “eye” will reveal hitherto unknown secrets of the universe and enrich man’s knowledge of life on earth.
by John Edwin Hogg
Nine years ago Palomar Mountain was a little-known mass of rock and earth in San Diego county, California. Being only 6,129 feet high, it is a mere foothill without even the distinction of altitude in a state where scores of perpetually snow-clad peaks rise to perpendicular heights of nearly three miles. A few Californians knew it as a good place to go deer hunting. Others, well-versed in state lore, had heard of it as the home of Nigger Nate, a fugitive slave who for many years lived the life of a recluse far up on Palomar’s forested slopes. Then suddenly, on October 28th, 1928, Palomar Mountain blared from the headlines of every important newspaper in the world. It was about to become a modern Olympus—the scene of the greatest single scientific endeavor ever undertaken by man. After years of painstaking study and research by astronomers in every part of the world, the board of directors of the Rockefeller Foundation had set aside a sum variously estimated at from six to ten million dollars to crown Palomar with an astronomical observatory housing a telescope beyond all previous dreams—an instrument twice the size of the present world’s largest, the famous 100-inch Hooker telescope on the summit of Mount Wilson. The machinery was set in motion to push back the mysteries of the universe by the inconceivable distance of a thousand million light years!
The volume of space within the previous range of man’s mechanical vision was enlarged eighteen times by the completion of the 100-inch Hooker telescope on Mount Wilson seventeen years ago. This will be multiplied by ten when the 200-inch instrument scans the heavens from the summit of Palomar some six or eight years hence. It will search space to find and photograph unknown astral bodies a billion light years distant from the earth. One light year is the equivalent of 6,000,000,000,000 (six trillion) miles. Multiply six trillion by one thousand million and you have the estimated range of the new telescope for prying into the mysteries of an unknown wilderness of the universe in terms of miles!
Nine years have elapsed since the Rockefeller Foundation made the funds available to the California Institute of Technology for carrying this stupendous scientific venture to completion. Another eight years will probably pass before the great instrument and the mammoth observatory for housing it are completed on the summit of Palomar. Why does such an important project move so slowly? Well, from intimate contact with astronomers in the construction and operation of the 100-inch telescope on Mount Wilson, the world-famous Bosscha Sterenwacht te Lem-bang, at Lembang, Java, and the present 200-inch monster to its present stage of development, the writer has learned not to expect such important scientific work to move like the building of a skyscraper or Boulder Dam.
Astronomers are a race of men apart from others. They are not motivated by financial considerations. They speak a language that sends reporters scurrying through the big dictionary for translations that can be read and understood by newspaper readers. They think in terms of a pure science that staggers human imagination—in light years and the history of astronomy, the world’s oldest science. A hundred years of scientific research is as so many days to them. Their own brief lives mean little to astronomy, where there is no time, no beginning to anything—and no end. Another generation of astronomers will carry on from the point where they leave off!
Three great buildings have risen on the Caltech Campus in Pasadena. They have been built and equipped at a cost of more than a million dollars. They are packed with intricate machinery and auxiliary astronomical equipment now being used to find the answers to a thousand and one problems for which there is no engineering precedent. A 200-inch fused quartz disc was cast at Corning, N.Y., and after being allowed to cool with care similar to that bestowed upon the Dionne quintuplets, was safely delivered in Pasadena. There, in the Caltech optical shops, an estimated four-year task of grinding and polishing will convert it into a concave mirror that is to become the reflector for the giant telescope. The mountings for the telescope, which will weigh 500 tons, including the 60-foot, latticed metal tube, are now being built in the Philadelphia plant of the Westinghouse Electric & Manufacturing Company.
It is interesting to note here that when the construction of the 200-inch telescope was first considered by the California Institute of Technology, the Rockefeller Foundation stood ready to provide funds for a 300-inch instrument. When the glass disc for the mirror of the 100-inch Hooker telescope was cast at St. Gobain, France, in 1913, it was considered that the physical limit of size in glass castings had been attained. Since then the process of fusing quartz into Pyrex glass has been perfected to the point that the building of a 300-inch telescope would now be feasible. But astronomers are a type of men who seldom favor bold experiments liable to end in disaster. Thus, after careful deliberation, they decided against at- tempting to build the 300-inch instrument. The 200-inch telescope, they believe, involves ample pioneering into unknown fields of engineering without such risks of failure as would be certain to arise in the attempted construction of an astronomical monster three times the size of the present world’s largest.
Some idea of such problems may be gained from the fact that a special railway carriage had to be built to transport the 200-inch disc from the factory in Corning, N. Y., to the Caltech shops in Pasadena. The glass is more than 52 feet in circumference —16 feet, 8 inches in diameter. Packing the boxing added several feet to these dimensions. The only possible method of moving such a shipment by rail was to stand it on edge. To do this and insure clearance under bridges and other railway structures the special railway carriage was built with diminutive wheels and an underslung floor. It cleared the rails by only inches. A study of all transcontinental rail lines then had to be made to find one that would permit the shipment to pass. The tightest squeeze on the route eventually chosen was in Buffalo, N.Y., where the lens box cleared an overhead viaduct by a scant three inches! Due to these track hazards, an inspection train moved ahead of the train carrying the disc. Then the caravan crawled across the continent at a pace never greater than 30-miles per hour. It moved only by daylight. Any sort of a major accident here would have set astronomy back by at least three years, to say nothing of financial loss. The glass for a 300-inch telescope would be 25-feet in diameter and could never be moved by rail at all. It would also be next to impossible to move such a disc from any ocean harbor in California to the summit of Palomar. Such considerations, however, would be only a few of the minor engineering problems that will be encountered if man ever attempts the construction of a 300-inch telescope. There would be many other greater difficulties.
Another factor that tended to discourage the attempted building of the proposed 300-inch telescope was that astronomers themselves feared the consequences to their own beloved science from the possible successful completion of such an instrument. They estimate that the field of research to be opened up by the thousand million light year range of the 200-inch telescope cannot be exhausted in less than half a century. The 300-inch telescope, assuming that it might have been built, might work to the detriment of astronomy by hurling it into confusion instead of advancing the science by orderly progression.
The astronomers of Caltech and the Carnegie Institute who will have full cooperative use of the 200-inch telescope hold out no hope that the instrument will tell us anything more than we now know concerning plant and animal life that may or may not exist on the other planets. But in the course of time they do expect it to give us the answers to many questions that have puzzled mankind for centuries. It may tell us what our world is, why we are here and where we are going as passengers on this little astral sphere whirling around through un-fathomed space. It may tell us whether our universe is exploding, is disintegrating by the dissipation of heat or is being replenished from sources unknown. It may prove or disprove the much-debated theory of Professor Albert Einstein to tell us whether we’re living in a “rubber universe” expanding like a toy balloon under pressure from within—a universe imprisoned behind curved walls or a creation that merely goes floating around through space which is without time, without a beginning, and without an end!
Research stimulated by the undertaking has already advanced astronomical technique by fully half a century—even six to eight years in advance of the monster telescope being trained into the heavens. Industrialists and inventors, anxious to have a part in this stupendous endeavor, have developed improved lenses, new photographic emulsions, new metals, new alloys and many previously unknown mechanical processes. It has produced a new process for aluminizing mirrors, which will be used for the first time in the Palomar instrument, taking the place of quicksilver used in the Mount Wilson observatory and in other reflecting telescopes. The new shops at Caltech are now literally crammed with instrumental improvements, specialized machines, and -tools born of new necessity.
In selecting Palomar as the site for the 200-inch telescope in preference to hundreds of others investigated in every part of the world, countless factors bearing upon the success of astronomy had to be taken into consideration. Such things as climate, clarity of atmosphere, freedom from aurora borealis and many others, are of tremendous importance. One of the chief reasons for the final choice of Palomar, however, was to avoid the mistake that was made some years ago when the 100-inch Hooker instrument was located on the summit of Mount Wilson.
Artificial light in the atmosphere is as much the enemy of astronomers as it is of a photographer working in the dark room. Go to the summit of Mount Wilson any clear night during the dark of the moon and you will soon see why many of the results anticipated for the 100-inch telescope have failed to materialize. You will look down upon one of the most spectacular displays of artificial light to be seen anywhere in the world—the lights of Los Angeles, Pasadena, Long Beach and scores of other cities stretching away like a carpet of diamonds from the mountains to the sea. Countless tourists go to the top of Mount Wilson every year just to see southern California looking like an inverted heaven with all the stars of the universe assembled into a vast panorama. It’s a magnificent sight but little does the average tourist realize how it be-devils astronomers.
When the Mount Wilson telescope was completed Los Angeles was a city of half a million souls. It is now a metropolis of 1,500,000 and every other city in southern California has experienced similar growth. While the average population has approximately doubled in the last sixteen years the use of electricity has increased ten-fold. As a result there are many nights when the atmosphere over Los Angeles County is so flooded with light that the astronomers on Mount Wilson have to knock off work. Here is a potential fortune staring some genius of illumination engineering right in the face. All this light that escapes upward from the lamps of mankind— BILLIONS OF KILOWATTS OF IT EVERY YEAR—is senseless waste!
On Palomar every condition was found to be favorable for the full use of the 200-inch telescope. Along with all the other considerations the astronomers were looking for a dark spot-one that must forever remain dark because the surrounding topography will not permit the building of any great and well-lighted cities. From the site of the new observatory the lights of San Diego find Los Angeles are visible on opposite horizons. But they’re far enough away not to worry the astronomers.
An astounding feature of Palomar Mountain is that there is nearly 30 square miles of fairly flat land on the summit. Thus, when the 200-inch telescope is set up inside a steel dome 135 feet in – diameter that will house it, we shall see the world’s first astronomical observatory where aviation will serve countless purposes of transportation. A large aviation field is now being prepared beside the 640 acres of grounds set aside for the observatory and auxiliary buildings. Instead of grinding over the tiresome drive now necessary to get up and down the mountain by the present motor roads, the astronomers of the future will journey to and from their mountaintop retreat like bees going in and out of a hive. The observatory will be a flight of only a few minutes from the laboratories and shops on the Caltech Campus. Movements of personnel and equipment will be largely through the air. A system of short-wave radio telephones will serve all purposes of instantaneous communication.
Some intimation of the discoveries anticipated from the 200-inch telescope may be gained from the fact that the physical limit of distance with the Mount Wilson instrument was reached when Dr. Milton Humason photographed the spectra of a nebula 240,000 light years away. It had an outward velocity of 26,000 miles per second. With the 200-inch sky camera it should be possible to obtain similar spectra at a distance of five hundred million light years. If the distance velocity already established still holds, such nebulae would have a speed of 55,000 miles per second. If such velocities are real and present theories concerning them are sustained; and telescopes more powerful than anything now contemplated are eventually built, astronomers believe nebulae will be discovered moving at the speed of light.
On favorable nights the 200-inch telescope will give us better photographs of Mars, Jupiter and our other planet neighbors than any previously made. The images will be no larger than those already made with the 100-inch instrument, but they should be clearer. This is due to the fact that in the 100-inch telescope the light rays are weakened by being spread over the photographic plate, making a slow time exposure necessary to record them. In the 200-inch telescope the light rays will be more concentrated. They will not be blurred when such photographs are made almost like snapshots.