First Light: The Search for the Edge of the Universe (16 page)

The eighteen-inch Palomar Schmidt telescope was a wide-field telescope; it yielded virtually a panoramic view. In one snapshot the Little Eye could photograph an area of sky larger than the bowl of the Big Dipper. The Little Eye contained two pieces of glass—a twenty-six-inch mirror and an eighteen-inch corrector glass at the nose. (Schmidt telescopes are rated in size according to the diameter of the corrector glass, not the mirror.) The Little Eye was one of the smallest professional telescopes in use anywhere in the world, and it bulldozed the sky. The Hale Telescope, on the other hand, drilled thin holes into lookback time. Even using electronic cameras, the Hale Telescope would require more than a human lifetime to make an overlapping mosaic of pictures of the northern sky. The Little Eye surveyed the entire northern sky more than once a year. The Big Eye had never caught an unknown asteroid cruising near the earth. “The eighteen-inch,” Gene said, “is the
fastest gun in the west.” He felt, however, that small telescopes did not attract government funding or the attention of private donors. The Shoemakers’ search for asteroids that could hit the earth was costing six thousand dollars a year. That was apart from Gene’s salary, which the Geological Survey covered when he was on the mountain. Much of the six grand went to pay for rolls of film. “The cookies,” Gene said, “are two dollars a throw.” The Shoemakers had been trying to raise some grant money to cover a salary for Carolyn, without luck. The Geological Survey would have been happy to cover her salary, but federal rules on nepotism prevented that. She had no choice but to value her time at nothing. She found earth-crossers for free. Gene said, “We’re getting too much of a bang for these bucks.” Dents on the Little Eye’s tube suggested that it had been getting more bangs than bucks for a long time.

B
ernhard Schmidt, the inventor of the Schmidt telescope, was born in 1879 on an island off the coast of Estonia called Nais Saar, which means The Island of Women—a whaleback of fields and forests in the Baltic Sea, five miles long, with a lighthouse at one end. The islanders dressed in the old costume and took their Lutheran religion seriously. Bernhard was a troublesome boy with a scientific bent who took bombs seriously, and he began designing and building them for fun. One Sunday morning, at the age of eleven, he skipped church and went into the fields to set off a pipe bomb of his own design. The material inside the pipe detonated unexpectedly, yielding a blast that must have rattled the windows of every church on Nais Saar. The blast also took off the sleeve of his Sunday suit, which unluckily had contained his right arm, which was also gone. He washed the bloody stump in a brook and waited in the woods for the churches to let out, and then ran home, afraid he would be punished for drenching his suit with blood.

After losing his arm, Bernhard Schmidt turned to the science of light. He began to grind lenses as a hobby, and when he grew up, he left the Island of Women. Around the turn of the century Schmidt landed in the town of Mittweida, in Germany. There he set up a workshop in an abandoned bowling alley, where he ground mirrors for amateur astronomers and lived on the small amounts of money that he got for his polished glass.

The difficulty in making astronomical mirrors lies in grinding a concave surface that will gather starlight and bring it into sharp focus. An astronomical mirror is a light scoop designed to pour a
large quantity of light into a tiny area, and the wider and deeper the scoop, the more light it can deliver rapidly to the film. In the language of optics, a mirror that can gather faint light quickly is said to be a “fast” mirror. The use of a fast mirror allows for brief exposures on film, thereby speeding up the astronomer’s work. A fast mirror is a steeply curved mirror. The curve known as a paraboloid is particularly good at gathering faint light, except that parabolic mirrors suffer from an unavoidable optical defect: only a tiny area at the center of a photograph taken with a parabolic mirror contains stars in good focus. Toward the edge of the photograph, the stars smear into commas. Astronomers avoid this defect by restricting the size of the film to a small area in the center of the field of view. In the Hale Telescope, for example, the area of good focus is about three-eighths of an inch square at the focal plane—an area the size of one’s little fingernail. Parabolic mirrors are terrible for searching large areas of sky.

Bernhard Schmidt became a master at shaping fast parabolic mirrors with his left hand. He kept himself going on brandy, cigars, coffee, and sweet cakes. With a fishtail of cigar stuck to his lip, Schmidt paced over his mirrors in the bowling alley all night, touching them a little with a polishing tool held in his left hand, keeping his empty right sleeve pinned up to prevent it from dragging on the glass. To get into the bowling alley he had to walk through the Lindengarten Restaurant. He told the proprietress, Frau Bretschneider, “Put out a good bottle of brandy for me, and if as I go by I pour myself some, then I’ll make a mark on the beer mat.” Schmidt kept his telescopes in an empty lot across the street from the Lindengarten Restaurant. On cold winter nights, when he was observing stars and simultaneously polishing glass, he kept rushing back and forth through the Lindengarten Restaurant, each time having a shot of brandy. The brandy got Schmidt coming and going, and by the end of a night the beer mat was covered with marks. “We used to make out very well with him,” Frau Bretschneider remembered.

Schmidt’s telescopes appeared to be screwed together out of scrap lumber and vegetable crates. One of them, a solar telescope, had a heliostat mirror that tracked the sun by means of a dripping water clock. He was shy and aloof; he never married. There is no
evidence that he liked women. He may have been homosexual, except that there is no evidence that he liked anybody, much. He was a frank pacifist. “Only one man alone is worth anything,” Schmidt once said. “Put two men together and they quarrel. A hundred of them make a rabble, and if there are a thousand or more, they’ll start a war.” So they did, in 1914. The German police began to watch him. They had no idea what was going on with the mirrors and the water clock, but they knew he was a pacifist, and since he was an Estonian, they concluded that he was an Estonian traitor flashing signals to Russian aircraft. They put him in a prison camp, where he suffered terribly. When the war ended, he returned to his bowling alley to continue grinding lenses.

In the years following the First World War, Schmidt’s work came to the attention of professional astronomers in Germany. Professor Richard Schorr, director of the Hamburg Observatory, at the risk of getting himself into trouble with the police, managed to extract Schmidt from his bowling alley and install him in a single-men’s dormitory at the observatory’s branch in the town of Bergedorf, outside Hamburg. There Schmidt lived for the rest of his life, a volunteer member of the staff and a chronic alcoholic, making mirrors for the observatory whenever he felt like it. They called him
der Optiker
B. Schmidt—The Optician B. Schmidt.

Professor Schorr gave him a basement room for a workshop, but
der Optiker
appeared to spend much of his time wandering around Bergedorf while talking to himself, apparently drunk, and puffing a tilted cigar under a brown felt hat pulled so low over his eyes that people feared he would catch the brim on fire.
Der Optiker
was terribly secretive. He allowed almost nobody to enter his underground vault. Opticians do not mix easily with humanity. As Mel Johnson, the optician who did some of the final figuring on the Hale mirror, explained to me, “All that scratching and dirtiness with people, it just kills you off.” The optician fears that people will feel the glass, and who knows where their hands have been. People will scratch their scalps, putting dust into the air, which can get between a polishing tool and the glass. One time, unbeknownst to Schmidt, a visitor picked up a polishing tool and took a few strokes with it on one of Schmidt’s mirrors, removing about a tenth of a millionth of an inch of glass. When Schmidt tested
the glass, he saw skid marks where the visitor’s tool had touched down. “Somebody has been fooling around with this!” he screamed. Professor Schorr always felt that Schmidt’s real skill as an optician lay at least as much in his eyes as in his hand, for when Schmidt looked at glass through his testing instruments, he could tell instantly where it deviated from a perfect optical surface.

Schmidt had such respect for glass that he dressed himself in a formal morning suit (a man’s long-tailed wedding suit) before he entered his polishing chamber. He hung a straw boater hat on a nail, revealing cropped, graying hair. He stood over a disk of glass and walked slowly in circles around it, watching the glass with a stern expression on his face, stroking the glass now and again with a small figuring tool faced with pitch, and kept his cigar stub unlit or let it burn in an ashtray to prevent ashes from dropping on the glass. His left hand looked like the hand of Michelangelo’s Moses—gnarled, monolithic, nourished with blood vessels. He knew the superiority of his hand to any polishing machine. “My hand is more sensitive than the finest gauge,” he said. His mirrors rested on bizarre contraptions made of crates and boards and ropes and pulleys. He refused to tell the world how he shaped his glass. “If I were to write it down,” he said, “it would so shock the astronomers and the opticians that I’d probably never get another order to construct anything.”

In the summer of 1929, an eclipse of the sun happened in the Pacific Ocean, and the observatory dispatched Bernhard Schmidt and a young astronomer named Walter Baade to the Philippines to photograph it. They left Hamburg in February on a steamship and did not return until September. The eclipse was blanketed by clouds, ruining some of the observations, which seems a pity for Schmidt and Baade after such a long journey. During the trip Baade snapped a photograph of Schmidt. In it Schmidt has no arms at all. Schmidt had hidden his one arm behind his back, because he was holding a bottle and he didn’t want it to appear in the photograph. The expedition’s main event, at least for the history of astronomy, took place on the steamship somewhere in the Indian Ocean.

Walter Baade never wrote much, but he left some stories with friends. What happened went something like this. It was evening,
as Baade later recalled. While Baade did not describe the setting, I think it is likely that the two astronomers were standing at the rail of their ship, watching a dark tropical sea slide past. The air would have been so clear that the stars contacted the horizon. Under the spell of the Clouds of Magellan,
der Optiker
would have steadied himself at the rail with his hand and remarked, around a fresh-lit cigar, that he had thought up a design for a telescope.

Walter Baade listened.

This telescope, Schmidt said, would be able to photograph a huge area of sky in a single exposure, and the star images it rendered would be needle-sharp from edge to edge on the film. It would be a very fast telescope.

Baade sensed that Schmidt had been thinking about this for a while.

First, Schmidt said, he would grind a mirror into a deep, hollow, spherical curve. That was easy—any two-fisted optician could achieve a spheroid. The reason that nobody used spherical reflectors in telescopes was that they produced horrendous distortions across the entire photograph, making such mirrors useless for astronomy. But what if one could install a correcting glass on the snout of the telescope, to reshape the light falling on the mirror? The correcting glass, Schmidt said, would have a toroidal ripple in its surface, an undulation so subtle that the glass would look to the untrained eye like a piece of flat window glass. But it would not be flat. It would introduce subtle distortions in the light. When the light bounced off the spherical mirror and hit a piece of film in the center of the telescope, it would be in complete focus from edge to edge of the photograph.

Baade was stunned. The potential of such a telescope must have been immediately obvious to Baade: it could be used to search the sky for moving objects. Baade told Schmidt that he must grind one of these corrector glasses as soon as possible.

Noch nicht!
Schmidt said. Not yet! First, he said, he must think up a method to polish his corrector glass. He would never, never, do a sloppy job on a piece of glass. Never! The praxis, the technique, he said, must be
sehr elegant
.

When the expedition returned to Germany, Baade and the observatory’s director, Professor Schorr, began to press Schmidt to make
his corrector glass. Schmidt answered them by walking calmly and aimlessly around Bergedorf, drunk, threatening to catch his hat on fire with his smoldering cigar. “Above all, he valued his independence,” recalled Baade. Abruptly Schmidt took off for the Island of Women. At some point—it is satisfying to think that it might have happened while Schmidt was tramping around those fields where he blew off his arm—he dreamed up another of his bizarre machines for polishing glass. He returned to Bergedorf. To Baade he remarked that he needed to know something about the bending characteristics of a thin sheet of glass. Baade gave him a handbook of physics. Schmidt studied the book and then donned his wedding suit and shut himself in his vault. He wanted nobody to see what he did.

When Schmidt had been in his vault for thirty-six hours, Baade began to worry about him. Baade finally went downstairs and found Schmidt unconscious near a wafer-thin, fourteen-inch disk of glass. “On waking,” Baade said,
der Optiker
“accepted cigars but declined coffee and sandwiches,” because, Schmidt said, he still had twelve hours of polishing left to go. Schmidt smoked a couple of cigars and shooed Baade out. The work climaxed in a frenzy of polishing.

The finished corrector glass was so thin that a pull with a pair of hands could have snapped it. As for his “elegant method,” Schmidt had placed the glass on a pan, like putting a lid on a cook pot, so that it formed a seal. He then pumped the air out of the pan while the glass bent downward and was sucked into the pan. He polished his glass flat, released the vacuum, and the glass popped up into a rippled shape.
Sehr elegant
!

By the summer of 1930, Schmidt had built a telescope to house his glass. One muggy Sunday afternoon he took Baade up to an attic window in one of the buildings at the Bergedorf observatory for first light. Ordinarily it is not possible to look through a Schmidt telescope by eye (the light comes to a focus in the center of the tube), but for this occasion Schmidt had evidently rigged up some kind of a prism to bring the light to an eyepiece. Schmidt pointed the telescope across a wide meadow, toward the Neuer Friedhof cemetery.

Baade squinted into the eyepiece. Baade noted a clarity of colors.
He noted that the edges of the leaves on the trees in the cemetery were razor-sharp.

“Can you read the names on the tombstones?” Schmidt asked.

“Yes,” Baade said, in awe. “But I can see only one thing: the optics are absolutely marvelous.” Baade then asked Schmidt just how big a corrector glass could be ground.

Forty-eight inches across, said Schmidt. Not any larger.

Then they put film in the telescope and photographed a tombstone. The letters of the name were clear.

That summer and autumn, Schmidt photographed the sky. Light passed through the glass, down onto the mirror, and bounced halfway back up the tube until it came to rest on the film—a simple and powerful imaging system. The films were circular and spangled from edge to edge with veldts of the Milky Way. One winter night he and Baade pointed the telescope horizontally and made an exposure of a windmill two miles away. The sails came out crisply. When they looked at the photograph through a magnifying loupe, they could count individual twigs on distant trees. As a matter of fact, it was a moonless night; the twigs had been illuminated by starlight.