Dr. Westerhout made the first of his achievements principally in a field known as radio astronomy in Holland in the years after World War II. He was among the youngest in a pioneering group of scientists taught and led at the University of Leiden by astronomer Jan Oort, who has been compared to a "modern Copernicus."
For centuries, astronomers have observed the universe with the human eye, aided by tools such as telescopes. Dr. Westerhout joined the nascent field of radio astronomy and set out to study the heavens using radio waves emitted by stars, galaxies and other celestial bodies.
He conducted his earliest research on a relic of World War II a large radar antenna left behind by the German military and later commandeered by the Dutch scientific community. Together with his colleagues, and on increasingly sophisticated equipment, Dr. Westerhout tracked the radio waves emitted by interstellar hydrogen gas to compile the first detailed map of the spiral structure of the Milky Way.
Astronomers describe that achievement as a major advance in the field. Scientists had long suspected that the Milky Way had the spiral structure of other galaxies, said Bill Howard, aradio astronomer who today lives in McLean and first met Dr. Westerhout in Leiden. But they were too "deeply immersed within the dust and gas within in our galaxy," he said, to know for sure.
"For the first time, we could see with some precision that what appears to be a random collection of stars up there is really organized," said Kurt Riegel, who was Dr. Westerhout's first PhD student at the University of Maryland and later headed the national astronomy centers at the National Science Foundation. "The radio observations .?.?. allowed astronomers to get a handle on our own galaxy."
At the time, Dr. Westerhout had not yet turned 30.
His work attracted the attention of scientist John Toll, a future president of the University of Maryland who at the time was building the school's physics department. In 1961, Dr. Westerhout received an invitation from Toll "out of the blue," he once recalled to come to Maryland and create an astronomy program.
Dr. Westerhout arrived in 1962 and built a program that later became a full-fledged department with undergraduate and graduate programs. "He basically got the program going," said Stuart Vogel, the current department chair. "He was the one who hired a lot of our astronomers and made us into what we are."
"If a person gets a PhD at Maryland," Howard said, " he is very well educated in the reserach area to make major contributions to the field."