Telescopes are time machines. A look - out is a look - back because light travels only so fast, and the Universe is a big place. Thus, light - years measure distance as well as time. Similarly, a visit to one of the great observatories is a more modest sort of trip through time. Rather than traveling via the laws of physics, the architecture, machinery, engineering and technology (or lack thereof) -- even the paint color -- form the transporting medium.

Established in 1904 under the direction of George Ellery Hale, the mountain - side location a mile above Los Angeles was one of the first to be chosen for the quality of the observing there rather than the proximity to major universities or rich benefactors. The white domes have a weathered look, despite the fact that their canvas exteriors -- an outer layer to keep the interior cool -- have been replaced by sheet metal. The 60" and 100" mirrors are cast of wine bottle glass, and the telescopes themselves look more like Erector Set projects than historical instruments of discovery. Indeed, for the first half of this century, Mt. Wilson was arguably the center of the astronomical universe. It is with these telescopes that Edwin Hubble measured enough galactic redshifts to confirm the expansion of the Universe and to displace us from its center.

With the tremendous development in Southern California in the interim, nights are no longer so dark at Mt. Wilson. But the seeing -- the steadiness of the atmosphere allowing optimal resolution of objects -- is still superb. The solar telescopes operate daily, and sunspot sketches are made routinely as they have been for decades. The 100" Hooker reflector, where Albert Michelson used his 20' beam interferometer in 1920 to measure the diameter of Betelgeuse, is now outfitted with a high - tech adaptive optics system to gain even more resolution.

In sharp contrast to the arching domes and curved walkways of the observatory grounds, straight pipes on stilts connect small modern domes to low, windowless buildings. These pipes are vacuum - optical guides bringing light from six, comparatively tiny mirrors sprawled among the historical domes. Despite the appearance, this too is a telescope, the CHARA Array interferometer. When completed in 2001, it will function as a single telescope 1800' across, capable of 200 microarcsecond resolution, the size of a nickel at 10,000 miles.

Mt. Wilson Observatory is a place where time can be seen extending from the distant past of galaxies tens of millions of light - years away to the present. There is a rich heritage of controversy, academics, politics and intense personalities in astronomy early in this century. Today, the latest in optical and electronic technology is being used to build telescopes unlike those serving astronomers for hundreds of years.  So this time machine runs forward too.

Moondark is written by Doug Miller and published on the web, in the Delmarva Star Gazers' Star Gazer News and in the Delaware Astronomical Society's FOCUS. Please address comments and suggestions todmiller@udel.edu. This document was last revised on 24 June 1999. All text and images copyright © 1999 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.