History

General History

In 1861 the Civil War began. A professor of Mathematics and Astronomy at Ohio Wesleyan University Hiram Mills Perkins left his teaching position to join the Union Army. The 6' 4" professor (who weighed only 97 pounds) was rejected by the Army as unfit for service. Undaunted by this, Hiram did the next best thing... he returned to his family’s pig farm in southern Ohio and raised hogs to help feed the Union Troops.

As anyone who has ever worked for a Defense Contractor can tell you, there is a LOT of money to be made selling things to the Army during a war. Hiram was no exception to this. However, as a devout Methodist and a man of deep convictions, Hiram felt it would be immoral to materially benefit from the pain and suffering of others (even in such an indirect way as providing food for Army troops). He therefore put his war profits into investments and returned to Ohio Wesleyan University after the war and lived out the rest of his life as a simple teacher.

The first task in constructing the observatory was to build the support pier to hold the telescope in place. Construction was contracted to the Warner and Swasey Company of Ohio, which built many large observatories around this time, including Yerkes Observatory near Chicago. Note the high-tech heavy construction “truck.”

As the observatory building neared completion, it became apparent that the telescope itself would require several more years before it would see first light. World War I had come and gone in Europe, destroying all of the major glass works which could produce large mirrors for telescopes.

Ohio Wesleyan University was able to persuade the National Bureau of Standards to undertake the task of casting the mirror for Perkins Observatory. After four failed attempts, a mirror was finally successfully completed. However, instead of the 60-inch mirror originally intended, the bureau had produced a 69-inch mirror. Although it required some changes to the telescope mount, they decided to use the larger mirror.

Prior to 1923, if you wanted a big mirror for your telescope, you went to Europe. All the glass-making factories of any importance were located there. But at the time he made his gift to the Ohio Wesleyan University, Hiram had stipulated that the mirror be made in America. In any event, since this was right after World War I, most European glass works were in ruins.

The task eventually fell to the U.S. Bureau of standards to cast the large mirror blank. It may seem odd that an organization created to standardize weights and measures would try its hand at mirror-making. The idea was that once they understood the techniques involved, this information would be passed on to private companies. From that point on, the United States would no longer be dependent on Europe for its telescope mirrors.

The first four attempts to cast a mirror blank were unsuccessful. The cooling process is the most critical part of mirror-making, and it is here that they encountered the most difficulties. After the glass pieces melted and flowed into the mold, the oven had to be cooled very, very slowly to avoid stress in the glass that can occur if parts of it are different temperatures. On the fifth attempt the glass blank was cooled so slowly that it took almost eight months before it could be removed from the oven.

Here is G. K. Burgess (right), Director of the Bureau of Standards at the time, and C. C. Crump, first Director of Perkins Observatory. Mr. Burgess is pointing out the 8-inch hole bored through the mirror blank. The core removed from the hole sits on top of the mirror.

And still the mirror was not finished. Having a 69-inch blank is all well and good, but it needed to be ground to the proper shape and polished to perfection. This took an additional three years. When it was finished, it was the first large telescope mirror ever made in the United States, or, for that matter, in the entire Western hemisphere!

At 69-inches wide and 9.5 inches thick, the mirror weighs in at about 4,000 pounds. almost two tons of glass! At the time, it was the third largest telescope mirror in the entire world!

The 69-inch mirror was installed at last in 1931, eight years after construction of the observatory began.

When it was completed in 1931, the Perkins Telescope was the third largest in the world. Perkins had one of the best Astronomical Libraries of the day, as well as facilities to accommodate visiting astronomers from all over the world. However, its location in Central Ohio left much to be desired. For one, all the people who live in Columbus and Delaware turn on their lights at night. The resulting light pollution severely limits the number of deep sky objects that can be observed. Also, the low elevation combined with typical Midwestern weather combined to make the big telescope quite limited in usefulness. Because of this, in 1961 the Perkins Telescope was moved to Arizona, where it is now a part of the Lowell Observatory, near Flagstaff. This was done to provide the much needed darker skies, fewer clouds, and a higher elevation. This was the largest telescope to ever be moved, before or since. (Don’t worry. We have another, smaller telescope – 32-inch... not too small – to replace it.) The move was paid for with a grant from the National Science Foundation. Remember, in the 1950s and 60s the United States was charging full speed ahead in the “Space Race”. Science education was the cause of the day, and the NSF had more money than they seemed to know what to do with.

Once the telescope was moved and reassembled, the 69-inch mirror stayed in use for just a couple of years. In 1932, just one year after the mirror was finished, Dow-Corning introduced a new glass-like material called “Pyrex”. Because of its very low coefficient of expansion, Pyrex was ideal for use in cooking, baking, and telescope making. Since Pyrex mirrors are so much better than crown-glass mirrors (like the 69-inch), a new mirror was cast for the Perkins Telescope. As it turns out, the new mirror was 72-inches across.

In 1964 a new science museum opened in Columbus, called COSI (the Center of Science and Industry). Two of the high-ranking staff members thought that the mirror would make an excellent exhibit and arranged for its extended loan from the Ohio Wesleyan University. They then rented a truck and drove to Arizona to pick it up. On the way back, they managed to burn out all of the gears in the truck except for one: first gear. So, the 69-inch mirror came back to Ohio from Arizona, all the way, in first gear.

The mirror stayed at COSI for 35 years. For most of that time it was on display on the second floor in the Earth Sciences Area. At one time, COSI designed a very nice series of exhibits on glass and optics with the mirror as its centerpiece. However, in the late 1980s they decided to take it off display. They didn’t move it into storage (4,000 pounds, remember?). Instead, a closet was built around it.

After some negotiations with COSI, it was agreed to return the mirror to OWU and Perkins Observatory. On Tuesday, September 14, 1999, the 69-inch mirror came home to Perkins Observatory from COSI. The mirror is currently in storage, but it is hoped a display area could soon be constructed to show off the mirror to the public once again.

Perkins Contributions