Examine these photographs closely in your browser. Especially notice the clock drive, and the table of eyepieces.

Anyone who has studied history in high school or college knows that a text book is a poor source of education. The images conjured up by even the most skillful of writers are at best fleeting. You are lucky to remember them until exam time. On the other hand, experience is a powerful teacher. An actual visit to the scene of a great event enables you to take home a memory which will live for years. The sites of many historical events have been preserved for our education and enjoyment. The scenes of other historical events, perhaps of less interest to our teachers, have been forgotten, and put to other uses. Finding these places, many of which may be of importance to you, even if not to the general population, can be a rewarding experience.

On a 1972 trip to Washington, D.C., I decided to visit the original location of the Naval Observatory's 26" refractor, where Asaph Hall discovered the satellites of Mars in 1877. The 26" refractor was at the time the largest refracting telescope in the world. It was Alvan Clark's first really large instrument, and it was this telescope that catapulted the Clarks to fame. Though the big refractor now enjoys a modern mounting on the outskirts of Washington, it was originally located in a building in town, "near the river and the Navy Yard", as one history book put it. That was our only clue.

Before departing for the nation's capital, a long-distance phone call was made to Bob Wright, President of the Astronomical League, and long a resident of the D.C. area. He said that he would be out of town while we were there, but would find out what he could about the old observatory.

We arrived on a very rainy day. Bob Wright had left a message that the original Naval Observatory, now called "The Old Transit House", was part of the present Navy Bureau of Medicine and Surgery, near the Lincoln Memorial. Calling the Navy Bureau of Medicine and Surgery, we were told that no one there was really sure which telescope had actually been located on the grounds. Now a "Transit House" surely does not suggest a very large refractor, and besides, the Lincoln Memorial is nowhere near the Navy Yard. We decided to gamble on a visit to the Navy Yard.

A quick call to the Pentagon – if you have ever called the Pentagon, you know how funny that is – resulted, after a number of transfers, in a conversation with the Navy's Public Information Office. They said that there were many old buildings in the Yard, but nobody was very familiar with their history. He recalled that there was an old employee there who had at one time made a study of the Yard's history, but he was now dead or retired; no one was sure which.

At this point the explorer within us rebelled, and we decided to visit the Navy Yard in person to seek out the hallowed spot. After all, who was better qualified to recognize an ex-observatory? After a meandering, error-ridden journey through parts of Virginia, Maryland, and the District of Columbia, we finally located the Yard. A quick drive through revealed no observatory, but we did find the Navy Yard Museum. Picking our way through assorted cannon, anchors, and capstans, we found our way to the office of the Curator. Yes, he had heard of the old Naval Observatory. After rummaging through several old filing cabinets, he announced that it was located at – care to guess? – the Bureau of Medicine and Surgery.

It was now 4:00 p.m., dangerously close to quitting time. The rain was heavier than ever, but a mad dash across town brought us to our goal in record time. Success was near! "Bu Med", as the Curator had called it, was located on the top of a modest hill. This was a good sign. When we had found the main building, we asked for the Public Information Office, and were ushered into the office of the Assistant Surgeon General, who doubled in this capacity. This, he told us, was indeed the site of the original Naval Observatory. The building next door had once housed the Great Refractor. Looking out his window, we saw our goal: a shining silver dome atop a rather large building.

The 9.5-inch Dome

The building is now used for office space. Even though the dome still sits regally above the roof, the observing room beneath it is now used as a reception room for several offices. No trace of the telescope's old pier remains. The wheels have been removed from the dome, and it is bolted in place. A number of large pictures about the room commemorate the telescope and that famous night 125 years ago.

But something was wrong. A 26-inch, f/16 refractor would have a focal length of almost thirty-five feet. This room was a scant twenty-five feet in diameter. As the twenty-six inch was not part of the observatory's original equipment, it was reasonable to assume that there had been another, smaller equatorial refractor which dated from its inception. (A later trip to the Smithsonian Institution revealed a 9.5-inch lens which had once belonged to the Naval Observatory. At f/16, this lens would have a focal length of 13-feet, fitting rather nicely into the Bureau of Medicine's modest dome.)

Further investigation revealed a likely solution to the problem. Extending south from the small dome was a narrow room, about 100 feet long. This must have been the transit room, hence the name "Old Transit House". The Washington Meridian, which was almost selected as the Prime Meridian, must have been defined by the instruments in this room. At the southern end of the transit room is a large circular room approximately 50 feet in diameter. This would in no way cramp the style of a 35-foot telescope tube. The room is at present topped by a conical roof, and it contains a large number of file cabinets; a necessarily inefficient use of a room specifically designed for another purpose. Conversation with the workers in this room revealed that they were totally unaware of its original use. There is no indication, by historical marker or photograph, that perhaps the most unusual objects in our solar system were discovered here.

Asaph Hall and Alvan Clark have been gone for many years, but to stand on this spot is to remember their achievement, and to somehow share in their great discovery. It is an experience to be recommended to everyone.

Back to top of page