Thousands of years ago, astronomers probably used the pyramids in Egypt and the towers and temples in Babylonia to help them study the sun, moon, and stars. There were no telescopes then. In time, astronomical instruments were developed, and as they became larger and more numerous, observatories were built to house them. Some observatories were built more than a thousand years ago.

An observatory has to be built in the right place, a place with favorable weather conditions, moderate temperatures, many days of sunshine and nights without clouds, and as little haze, rain, and snow as possible. It must also be away from city lights and neon signs, which make the sky too light for good observation.

There are buildings which include living quarters in addition to telescopes. The instruments are housed in structures of steel and concrete. The building for the telescope is constructed in two parts. The lower part is stationary, and the upper part, or roof, is in the shape of a dome which can be rotated.

The dome has a “slit” which opens to permit the telescope to look out toward the sky. By rotating the dome on a track, the slit can be opened to any part of the sky. Both the dome and the telescope are moved by electric motors. In a modern observatory the astronomer only has to punch a number of buttons to move the equipment.

Of course, in order to see, the astronomer must always be near the eyepiece of the telescope or the camera attached to it. So, in some observatories the floor can be raised or lowered, or there is an adjustable platform.

Astronomers don’t depend on their eyes alone to observe the skies. They have many complicated instruments and attachments to the telescope, such as cameras, spectroscopes, spectrographs, and spectroheliographs, all of which provide them with important information.