If we are what we eat, Maarten Schmidt is composed partly of sand dabs. Those fish are a tasty part of the fallout from the Big Bang that got the Universe rolling and led to all things bright and beautiful. Schmidt, one of the Universe's more complicated efforts, is tucking into sand dabs as he talks about his vocation, astronomy.

We are, he says, only superficially what we eat. We really are stardust. Stars produce life and dust produces stars. How, exactly? He soon will have a new instrument for investigating that and other questions.

Astronomers are detectives whose evidence is the light that streams toward us, passive but informative about the formation and evolution of stars. Radically improved technologies have enhanced the light-collecting capacities of existing telescopes. Soon, however, there will be a new telescope with a 10-meter reflecting mirror. It will have four times the light-gathering capacity of the telescope at Mount Palomar.

The W. M. Keck Observatory will be the result of the largest private gift, $70 million from the Keck Foundation, ever made for a scientific undertaking. Its mirror will be a mosaic of 36 hexagonal mirrors six feet wide. They will be coordinated and aimed by a computer making adjustments one-one-thousandths the diameter of a human hair several times a second.

Stars do not twinkle in space. They twinkle because of atmospheric distortions of light. The site for the new telescope, atop an extinct (we hope) volcano in Hawaii, is considered the world's best site. Several other telescopes are operating there, 13,600 feet above most of the distorting dust, clouds, moisture and urban lights of Earth.

It has been said that if God revealed to us all the secrets of the universe, we would be sunk in apathy and boredom. That gives too many people too much credit for curiosity. But worldwide, there is not enough observatory time to accommodate all the curiosity of astronomers.

They would like to confirm the suspected existence in a distant galaxy of a black hole (material so dense its gravity swallows light) containing a billion suns. In another galaxy there is a star that may be 30 times hotter than our sun. It would be fun to know if that is so, or if one of Saturn's moons really does have an atmosphere similar to what Earth's once was.

Unfortunately, science requires continuity, so there is a mismatch between the needs of science and the way Congress budgets. NASA's next splashy project, a permanently manned space station, will cost at least $8 billion, plus operating costs. It is worthwhile, because the costs are not excessive when spread over several decades, and because of the element of serendipity: ambitious scientific enterprises are apt to have unanticipated benefits.

But the space station may be a bureaucratic black hole, swallowing scarce funds and starving basic science. True, an argument for the station is the "coattail effect": support for all space science is pulled along by the public constituency excited by manned projects. But in the budgetary triage that will be triggered by the Gramm-Rudman process, pure science is apt to be an early casualty.

Sen. Pat Moynihan says Gramm-Rudman is a recipe for little government at home and little influence abroad. He could have added "and for little knowledge regarding some of the great questions of human experience."

Consider this. The Nixon White House almost did not approve the space shuttle. Congress nearly killed it five times. In one vote, the shuttle survived only because a confused congressman who wanted to kill it miscast his vote.

The shuttle has been disappointing in terms of costs and commercial applications. But it has been an instrument of serious science. And it can deliver large payloads, such as the space telescope. The deployment of that glorious instrument will be the high point of a year in which much of the most important news in newspapers will concern space science. Enjoy it while you can. Philistine conservatism is going to try to balance the budget by turning down the intellectual light.

This month, the Voyager 2 spacecraft, passing the 3 billion-kilometer mark, will provide the first detailed glimpse of the planet Uranus. In eight days in March, six spacecraft sponsored by four nations will intercept Halley's comet. In May the United States will launch probes toward Jupiter and beyond. And in August the space telescope will be orbited, the greatest leap forward in observational astronomy since Galileo assembled his telescope -- with a lense four centimers across -- in 1609.

The space telescope will be the subject of the next column, from across the continent -- from the city that, suddenly next summer, will be at the center o world science: Baltimore. Yes, Baltimore.