ARIZONA'S NEW BIG EYE

New Big Eye OFFICIAL U. S. NAVY PHOTOGRAPHS

Besides of the building. They are moved up and down hydraulically, more motors doing the pumping. Thus is the wind prevented from vibrating the telescope. This makes it seem that at one moment one is standing inside a building, spotless and shining. The next moment, he stands in a bright box with its lid off. In a following moment he is standing in a "deep well," when the sides go up.

An additional convenient feature incorporated into this building is its movable floor immediately surrounding the telescope. This floor is raised and lowered at the astronomer's will, hydraulically. Such a floor does away with the necessity of an overhead crane for applying heavy instruments to the telescope or removing the 40inch mirror for re-aluminizing.

The 40-inch telescope itself is the last instrument designed by the late George W. Ritchey, famous telescope maker. It was put into commission at the U. S. Naval Observatory, Washington, D. C. in 1934. The "big eye" was the major light-gathering instrument there. This machine is the largest ever built from a Ritchey-Chretien design, the optical arrangements conceived by Henri Chretien. When the equipment was transferred to Flagstaff, it underwent considerable modernization in its details, but remained substantially as built otherwise.

To "follow a star," that is, to keep a star centrally in view of its mirror over a prolonged period, either while a photographic negative is being exposed, or critical eyeexamination takes place, the telescope must be able to move continually and smoothly. Often an astronomer will wish to make a "sweeping view of the sky," say, to follow a comet's flight. This requires the telescope's starfollowing arrangements to be variable and quickly changed. The 40-inch scope at Flagstaff Station is moved by electric motors electronically controlled from the panel-desk at the instrument's side and rear.

It is also interesting to note that arrangements have been incorporated whereby the telescope must be in a certain lowered position before the motor operating the rolling roof will function. This eliminates possibility of the roof being moved while the telescope is in use-or should an astronomer forget. Also, the roof motor will not operate if any of the "wind shield walls" are lifted. But wait a minute. What does the Navy want with an astronomical observatory anyway? What does astronomy have to do with battleships, submarines and aircraft carriers? Well, when men go down to the sea in ships they do not find sign posts telling them how to get where they wish to go-except in the stars and by the sun. So, good sailors have to have a bit of astronomy mixed with their beans! Too, the Navy is much interested in Timeon the dot time-and that too comes from the stars! Arizona's new 40-inch eye looks out upon the sky from a 7,600-foot elevation. This is some 600 feet higher than Flagstaff, which place one can plainly see from the observatory's front door.

It is frequently recited-and more often true-that Arizona's climate is determined by the altitude. The higher, the cooler, and the wetter. But like the popular song, 'Tain't Necessarily So! In the case of this observatory site it would appear considerable of that sort of "so" was present. In summer, the night temperature is some ten to fifteen degrees cooler than in Flagstaff, while in winter, like temperatures are from ten to fifteen degrees warmer!

This telescope and observatory are presided over by Dr. Arthur A. Hoag. Dr. Hoag is a tall young man with a most pleasant personality. He has an extraordinary fund of knowledge, not only relative to the telescope, its design, its history, its abilities, etc., but his knowledge also covers much physical data of the surrounding countryside as well.

A second astronomer at the Flagstaff Station is Dr. Elizabeth Roemer. Dr. Roemer is a specialist whose present work in astronomics is principally with comets and astroids. She writes the bimonthly column "Comet Notes" appearing in publications of the Astronomical Society of the Pacific. Dr. Roemer is also interested in measurements of visual binaries, or "double stars."

The facilities at the Flagstaff Station also include a very complete machine shop and the services of an excellent instrument maker, Joseph P. Egan. We were shown some of the intricate pieces of equipment which Mr. Egan had built for both the telescope and its affiliated apparatus. We have seen no better of like kinds of instruments at Mt. Wilson or Palomar.

Within the same building which houses the instrument shops are included a photographic darkroom with all developing, printing and enlarging apparatus necessary to the proper functioning of such an observatory. Here also are two offices, a kitchenette, and sleeping quarters for visiting astronomers. A large instrument room, storage space and a garage adjoin.

There is, of course, much necessary supplementary technical equipment pertinent to the complete work of the 40-inch eye. These buildings, as well as the one occupied by the telescope, are on the same floor level. This allows the moving of equipment easily.

Says Dr. Hoag, "The clear, cool, dry climate of the Flagstaff area leaves little for an astronomer to desire. Clear nights are three times more frequent here than in Washington. The air here is much more transparent. However, all these are not the most impressive attribute of this region. Here at the Station, the night sky is really dark. It is only 1/15 as bright as in Washington! To an astronomer, such a condition is highly important."

The "seeing" in Flagstaff region has always enjoyed a good reputation. More than sixty years ago, Percival Lowell located his private observatory on Mars Hill, just above Flagstaff. It has been in continuous operation since, and has contributed much to the science of astronomy, as well as had a number of "firsts" to its credit.

In moving its 40-inch equipment to the Flagstaff area, the Naval Observatory has not isolated its astronomers, scientifically or academically. Not only are brother astronomers present at Lowell, but those of the Atmospheric Research Observatory at the Arizona State College, Flagstaff, are close by.

All this makes the Flagstaff area of considerable astronomical importance today. It is quite likely this importance will grow in the future.