First Light: The Search for the Edge of the Universe Read Online Free Page B

through the hole in the center of the mirror. Although the camera is enormous (for a camera), from a distance it looks no bigger than a rivet fastened at the bottom of the Hale. Gunn built this camera from scratch in a Caltech basement known as the Wastebasket, where he received much help and many used parts from certain Caltech engineers and technicians who happen to be experts in the arcana of trash, and who are known collectively as the Wizards of the Wastebasket. In certain ways, 4-shooter resembles a scientific package on a spacecraft: it contains a variety of quartz lenses and mirrors, forests of gold connectors and gold-plated parts, and advanced imaging sensors. In other ways it resembles an outrageous kludge: it contains tangles of stainless-steel plumbing, surplus wires, junk motors purchased at deep discount (for ten cents on the dollar or less), movie projector belts, a broken razor blade, Ensolite foam, piano wire, grease, glue, and small, powdery crystals of dried sweat.
    A leading scientific instrument usually remains on the cutting edge of science for a few years, until a better instrument comes along, but the Hale Telescope has been breaking trail into the deep for forty years, principally because of the Palomar gadgeteers. The Hale is no longer the largest telescope on earth—Caltech recently built a larger one, called the Keck Telescope, on Mauna Kea in Hawaii, which has a mirror made of glass segments that add up to the equivalent of a four-hundred-inch telescope. The Hale Telescope is, however, world-class. It contains a suite of hypersensitive instruments, of which 4-shooter is one. These instruments, together with the size of the telescope’s mirror, make the Hale one of the best telescopes on earth. The Hale is a masterwork of Depression engineering, the Apollo project of the 1930s. Colossal, welded, gray, aloof, massive, agile, apparently indestructible, and uncompromisingly and magnificently extragalactic, the Hale Telescope stands among all telescopes as the climax of dreadnought design. There will never be another telescope like the Hale, because, in the first place, no amount of money could build the Hale Telescope today, and in the second place, the philosophy of telescope design has changed. A new generation of earth-based telescopes is being built, containing large mirrors hung in airy frames, built more like aircraft than ships. Then there is the Hubble Space Telescope, which is a canister that was tipped into orbit three hundred miles above the earth, from the cargo bay of the space shuttle
Atlantis
. But for the time being, the Hale is the world heavyweight champion. The Hale will likely continue to be regarded as one of the world’s great telescopes until well into the twenty-first century.
    The Hale is a versatile telescope. In addition to its two-hundred-inch primary mirror, it contains a total of eleven smaller mirrors that can be moved and angled in order to reflect and condense light into various points inside or near the telescope, where instruments can be placed. The Hale is a refinery for light. It collects a huge amount of starlight and pours it into a minuscule area. When 4-shooter is plugged into the Hale, starlight lands on the Hale’s primary mirror and bounces up to a small secondary mirror (four feet across) at the top of the telescope. The light then bounces downward into 4-shooter, sitting in the hole in the two-hundred-inchmirror. By the time the starlight enters 4-shooter, it has been narrowed down from a beam two hundred inches across into a beam fourteen inches across. The beam of starlight enters a window in 4-shooter, where it is further shrunk and bounced among mirrors. Finally it lands on four electronic chips known as CCDs. Each chip is the size of a child’s fingernail. In the end, the light that falls on the main mirror of the Hale Telescope—209 square feet of starlight in all—is distilled onto four chips having a total surface area equal to one postage