Crew Maps Night Sky : Astronomy: Technicians photograph space to give astronomers a road map to the universe. It’s sometimes boring work, until they remember its potential importance.
This is the drudgery that leads to scientific discovery: the incessant clacking of a motor, a technician licking the cream center from a split Oreo cookie, and another talking at 4 in the morning about soap operas.
A third worker suggests a soap opera title that would mirror life here, at the Palomar Observatory: “As the Dome Turns--The Continuing Saga.”
As she laughs, the dome is turning: the spherical roof above the 48-inch Oschin telescope atop Mt. Palomar. A 14-inch-square piece of chemically treated glass is being exposed for more than an hour to the night sky as the telescope moves almost imperceptibly so that the star images won’t be blurred by Earth’s own rotation. The clack-clack-clack is the sound of electrical relays as motors nudge the telescope ever so slightly upward and to the right.
Night in, night out--except for Christmas Eve and Christmas Night--these specially trained telescope and photographic technicians gather to soak in Mt. Palomar’s most glorious view--not the pines and grazing meadows and gloriously blue sky by day, but the never-ending speckles of galaxies, quasars, asteroids and stars framed by the black sea of night, far too faint to be seen by the unassisted eye.
These are celestial cartographers documenting the northern sky, preparing a sort of Thomas Guide of the stars that will serve as a reference atlas to direct astronomers around the world as they search for answers in the universe.
Job Training
The ones who work here are not formal astronomers with doctoral degrees. They were hired for their various technical expertise, trained on the job and paid about $25,000 a year to photograph the night sky for later inspection, not unlike a nurse preparing the patient for a physician’s scalpel.
The quiet routine of a night within the 22-year-old dome--peaks of activity separated by tiresome stretches of whiling away the hours--belies the scientific discoveries that are probably being made. The place doesn’t have the aura of astronomy at the vanguard. In a downstairs office, below the dome’s telescope, there is only one computer--the kind you can buy off the shelf in an electronics store.
There are no video display terminals allowing a glimpse into what the telescope itself is seeing--just a darkroom where the glass negatives are carefully developed, dried and packed for shipment to Caltech in Pasadena for later inspection. A refrigerator is stocked with soda and a couple of frozen dinners. The microwave oven is mostly for popcorn. Hardly high-glitz stuff.
The Oschin telescope is no headline grabber. The Sky Survey started two years ago, and, after some false starts, about 500 plates have been successfully exposed. The survey will not be completed until the mid-1990s. Not much breaking news here.
But someday--maybe in a week, maybe in 10 years--an astronomer may inspect one of the exposed glass negatives and discover a heavenly body never before spotted by the human eye, expanding our knowledge of the universe.
It’s 5:30 p.m. and the moon has set, half an hour behind the sun, giving way to a black, cloudless sky--perfect conditions for some astronomical work.
Jean Mueller, Cindy Brewer and Dave Mendenhall are in an office below the Oschin telescope, which was put to work in 1947 as an instrument specifically designed to photograph the stars. Unlike the neighboring and more famous 200-inch Hale telescope, through which the universe’s most distant and faint objects can be detected and studied, the Oschin is a wide-angle telescope that provides broader vistas of the sky.
The full moon would fill up the Hale’s view of the sky. But a sky view 13 moons wide can be photographed through the Oschin’s 48-inch lens opening. Despite their wider view, Mueller, Brewer and Mendenhall will still need to take 894 pictures of the northern sky to complete their celestial scrapbook, so that astronomers on more narrowly focused missions will know where to train their larger telescopes. They will take two more rounds of photos--with different filters, in order to detect stars emitting different colors of light--for a final complement of 2,682 pictures.
Under the best of circumstances--a long, dark, cloudless night--six pictures can be taken. That makes it a frustratingly slow process, but Mueller said the rewards, however esoteric, are mind-boggling.
“You know for a fact you’re seeing objects never seen before by a human,” she said. “That’s instant gratification.”
Mueller will spend part of the night comparing the newly exposed photographic plates with ones taken 35 to 40 years ago, when the first survey was conducted. Because of advances not only in the hardware of the telescope but, more important, in the Kodak film emulsions, objects that were three or four times too faint to have been spotted in the late 1940s and early 1950s can now be photographed. Put another way, the new film material allows the Oschin to detect, in rough terms, objects twice as far away.
How many more celestial objects will be found remains to be seen; it will take years for scientists around the world to pore over the plates being exposed by the nighttime trio.
By comparing the findings of the new survey to the first one, astronomers will also be able to determine just how the structure and mass of the Milky Way has shifted over the years.
“I have no doubt that discoveries will be made on these plates 15 years from now,” Mueller said. “It depends on what the people will be looking for. But these plates will be keeping astronomers busy for generations to come.”
They are exposing their first plate for the evening so they can make sure that the instrument is in focus for the night’s work.
The plate sits in a frame in the middle of the telescope’s tube, catching the light that enters the lens of the scope and that is collected by the 72-inch spherical mirror at the bottom. The mirror focuses the light rays back up the tube, onto the glass plate coated with chemicals, to preserve the photons of light.
The characteristics of the new-age photo emulsions--which produce high-resolution negatives--require exposures of an hour or longer and supersensitive developing techniques that last two hours from start to finish. But the most critical and difficult work, Mueller said, is in making sure the picture is in focus.
The photographic plate must be placed within 30 microns, or one-10th the thickness of Scotch tape, of the optimum position within the telescope’s tube in order for the light rays to be in pinpoint focus. Even a piece of dust in the plate’s frame, or the changing night temperature on the glass itself, can affect that focus. So throughout the night, the telescope may be adjusted by mere microns.
The first plate is developed. Mueller puts it beneath a microscope, takes some readings and telephones the information upstairs to Mendenhall, who pushes a button on the telescope’s control panel to place the frame correctly within the telescope tube, for the first Sky Survey exposure of the night.
Back downstairs, Brewer flips through a computer printout showing, in columns of numbers, the nightly coordinates of locater stars that the telescope will home in on to photograph that particular piece of the sky. She picks a star in a sky field that has not yet been photographed, and sends the coordinates upstairs to Mendenhall. He twirls a dial on the telescope’s auto-guidance device, then pushes a button that swings the telescope into position. The slit in the dome follows suit. A smaller telescope attached to the larger one finds the target star, and locks in to its brightness so it can track it during the exposure. Everything is set; the lens is opened, and Mendenhall, who had been working in virtual darkness, walks downstairs into the warm office, where he will kick up his feet and work his way through Carlos Castaneda’s “The Eagle’s Gift.”
Brewer now peers at a readout that shows the rate of light photons hitting the glass plate. Based on that, she determines the exposure time on the plate to that part of the sky--an exposure that changes based on how bright that part of the sky is that night.
It is just after 6 p.m. They will be here for 12 more hours.
Despite all the high-tech care, mistakes, although rare, sometimes happen.
There was the time they forgot to take the giant dust cover off the lens--an error that went unnoticed until the blank plate was developed. (After all, they never actually look through the telescope itself during an exposure.)
Or the time they forgot to throw the switch so the dome and telescope would move in sync with Earth’s rotation.
Or the time they put the film frame in backward, or the time they put the glass plate into the frame, but forgot to raise the frame into the telescope so it could be exposed.
Or the time they forgot to close the box of unexposed glass plates when the lights were turned on.
Danger. Humans at work.
It’s 7:30 p.m. and Mendenhall drives over--with only his car’s parking lights shining his way so he won’t pollute the darkness--to the nearby lodge nicknamed “The Monastery” to snatch some Oreo cookies. The Monastery houses visiting astronomers and graduate students, who sleep by day while working at the mountain’s other telescopes.
Brewer and Mueller, who are on the observatory staff full time, live in their own small cabins on the observatory campus. Mendenhall also is an observatory employee, as opposed to a visiting scientist, but lives a few miles away in his own mountaintop ranch home, where he helps manage the family cattle business.
“I love being part of scientific discovery,” said the 30-year-old Brewer, an Iowa native who spent 19 years in the Navy as an electronics technician, training that serves her well here. When she got out of the Navy, she sought out Mt. Palomar’s solitude because she basically does not like being around crowds of people.
She works a shift of 10 nights on, four nights off. She sees her husband, still serving in the Navy and stationed in Long Beach, only on her days off.
She likes being up here, virtually unsupervised by the actual astronomers who work at Caltech, which owns Palomar Observatory.
“We’ll probably never see astronomers inside here,” she said. “To do quality work, we need the same regimen. That’s why we’re the same ones doing it night in, night out. The astronomers may send down orders to us about shooting a particular sky field because there’s been a request for one in particular. But essentially we’re on our own, doing our job.”
Now it’s 8:15 p.m. Mendenhall, back from his cookie run, is upstairs, putting in the night’s second glass plate.
In the downstairs darkroom, the first Sky Survey exposure of the night--a look through a spiral arm of our own Milky Way--has been developed, and Mueller cringes. Across the frame are two dark streaks--the lights of an airplane that flew 10,000 feet overhead. An untold number of previously undiscovered galaxies millions of light-years away may have been obliterated by an airplane bound for Ontario or March Air Force Base. Two hours of work--and a $100 photographic plate--down the tubes. The plate is unusable.
8:40 p.m. A consolation bag of popcorn is taken out of the microwave and there is general complaining because a lot of the kernels didn’t pop.
Even the astronomers making heralded discoveries at the neighboring, 200-inch Hale--the world’s most valuable land-based tool for inspecting deep space--look to the little guy next door, the 48-incher, for help.
“Without it, we’d be lost,” said J. B. Oke, who, along with fellow Caltech astronomer Marshall Cohen, is in the computer control room of the more famous Hale, studying the evolution of distant galaxies. “It gives us the road map so we know where to look.”
The Oschin is “the most-used astronomical instrument in the world,” Cohen said.
Robert Brucato is the assistant director of Palomar Observatory; he spends some time here and some time at his main office in Pasadena. “So much of science is perceived to be gee-whiz stuff, the ‘Eureka! I found it!’ ” he said. “But the real progress is made through the drudgery of picking away at the sky, piece by piece.
“When the 200-incher was being designed, we didn’t know what the sky looked like and what limits the 200-incher would reach. It was like navigating without a map. We didn’t know where to look. So we built the 48-incher to help us.”
The first Sky Survey was conducted between 1947 and 1956; those photographs have since been shared with more than 100 astronomers worldwide, who use it as a reference guide to zero in on their particular area of work.
Given advances in both the construction of telescope lenses and the chemical makeup of photo emulsions, the new survey will provide more celestial street signs and landmarks for astronomers.
The Hale telescope now “reads” the light in space through a 3-inch-square electronic device covered by 6 million ultra-light-sensitive silicon chips--which is then converted digitally by a computer to shades of black and white and transferred to a video monitor. The Oschin produces images of space the old-fashioned way, through black and white photos.
A similar survey--this one of the southern sky--is being conducted in Australia, so astronomers will be gifted with an all-encompassing, updated sky map.
It’s 10:15 p.m. The second plate of the night has been developed--showing this time not one but three separate airplanes having crossed above the telescope, leaving six black lines as unwanted souvenirs. “Shoot!” Mueller exclaims: 0-for-2 on what were otherwise perfect exposures.
It isn’t too unusual for the first exposure of the night to be ruined by an airplane, but two bad plates causes audible irritation.
Astronomy is Mueller’s life. The 39-year-old former librarian pores over the negatives as they come out of the wash, and is typically back at the dome even on her days off to further scrutinize the plates.
Mueller has discovered 10 supernovas, four asteroids and a comet, which now carries her name. It is due to fly by Earth again in late 1995. “I was just scanning the plate, and there it was,” she said.
“When you inspect the plates, you almost can’t think about what you’re looking at, because it would be so overwhelming,” she said. “When you realize how much is out there, it keeps us in our place.”
Brewer offers a similar perspective.
“You look at plate after plate of stars and galaxies that go on forever and get fainter and fainter and fainter,” she said. “It’s mind-boggling. I’m not a religious person, but it makes you think about God. What if the big-bang theory is just bunk? What if God just threw out his arms one day and there it all was?”
Mendenhall, 46, a quiet, no-nonsense man, began working at the observatory 10 months ago. He is a fourth-generation mountain resident who, as a child, dreamed of working inside one of the domes. Having worked the family ranch and having spent 10 years as an air traffic controller, he was hired for the Sky Survey last year because of his high-tech mechanical expertise.
“I like this project because it’s finite, with a specific goal,” he said. “It’s been done only one time in history, and this may be the last time. I want to be a part of it.” With a smile, he added: “I like to make the telescope go.”
An Oscar Wilde quote is printed on a placard stuck to the wall of the office: “We are all lying in a gutter, but some of us are looking at the stars.”
It’s half-past midnight. The third plate has been developed--and it, too, is marred by the lights of yet another airplane. Mueller debates whether to go for the chicken or linguine frozen dinner. Linguine it is. Mendenhall has his feet up on the desk, eyes closed. Brewer just sits there, looking at the readout of the rate of photons exposing the plate like some late-night movie.
Boring.
2:17 a.m. The fourth plate came out fine, with no airplane streaks. Finally, a decent exposure! The fifth plate is now being exposed. It will be finished at 3:25 a.m. Is there time for a sixth plate? “We have until 5:15 to finish that exposure,” Mueller said. “Piece of cake.”
3:50 a.m. Mendenhall is working his way through “The Eagle’s Gift.” Brewer is filling out the log sheet for the night’s exposures. Mueller is developing the fifth plate. It’s 42 degrees upstairs in the dome.
4:45 a.m. “Our last exposure will be done five minutes before astronomical twilight,” Brewer said. “It looks like we’re going to eke out every photon of the night sky. The photons are crying out for immortality on our plates.”
Getting a little punchy now.
5:02 a.m. The fifth plate is developed and looks great. No airplane streaks. The sixth and final plate of the night is now out of the telescope and in the developer. Mendenhall goes upstairs, secures the telescope, closes the dome and goes home, his chores done for the night. “When I wake up,” he said, “I’m going to do some real work. Cut firewood.”
At 5:31 a.m., Mueller is looking at the last plate and her attention is drawn to a particularly bright galaxy. “Oooooh!” she says to no one in particular. “Maybe I’ll come in tomorrow after all.” It is supposed to be her day off.
The night’s score card: Out of six plates, three are ruined by airplanes and three are keepers. It’s now nearly 6 a.m.; the eastern sky is turning a blood red. Distant roosters are announcing the new day, and the surveyors of the stars are calling it a night.
