Allan R. Sandage | Leading astronomer, 84

Allan R. Sandage, 84, who spent his life measuring the universe, becoming the most influential astronomer of his generation, died Saturday at his home in San Gabriel, Calif.

The cause was pancreatic cancer, according to an announcement by the Carnegie Observatories, where he had spent his entire career.

Over more than six decades, Dr. Sandage was like one of those giant galaxies that sit at the center of a cluster of galaxies, dominating cosmic weather. He wrote more than 500 papers, ranging across the cosmos, covering the evolution and behavior of stars, the birth of the Milky Way galaxy, the age of the universe, not to mention the Hubble constant, a famously contested number that measures the rate of expansion of the universe.

In 1949, he was a young Caltech graduate student, a self-described "hick who fell off the turnip truck," when he became the observing assistant for Edwin Hubble, the astronomer who discovered the expansion of the universe.

Hubble had planned an observing campaign using a new 200-inch telescope on Palomar Mountain in California to explore the haunting questions raised by that mysterious expansion. If the universe was born in a big bang, for example, could it one day die in a big crunch?

But Hubble died in 1953 just as the telescope was going into operation. So Dr. Sandage, a fresh Ph.D. at 27, inherited the job of limning the fate of the universe.

"It would be as if you were appointed to be copy editor to Dante," Dr. Sandage said. "If you were the assistant to Dante, and then Dante died, and then you had in your possession the whole of the Divine Comedy, what would you do?"

In 1991, Dr. Sandage was awarded the Crafoord Prize in astronomy, the closest thing to a Nobel for a stargazer, worth $2 million.

In later years, Dr. Sandage withdrew from public view. But even after retiring from the Carnegie Observatories and becoming ill, he never stopped working; he published a paper on variable stars in June.

- N.Y. Times News Service