Benjamin F. Peery, 88, an astrophysicist who spent the second half of his career as a professor at Howard University, died Nov. 30 at his home in Silver Spring. He had dementia.

An expert on the chemical makeup of stars, Dr. Peery was a professor at Indiana University for 18 years before deciding to shift to Howard in 1977. His aim was to train young African American astronomers, he told The Washington Post in 1991, but it was difficult to coax Howard students into the field.

"It can be daunting to enter a field that has so few of your kind in it," said Dr. Peery, who estimated at the time that of 6,000 members of the American Astronomical Society, only 10 were black.

He served as chairman of Howard's astronomy and physics department before becoming an emeritus professor in 1992.

He did research at the Kitt Peak National Observatory near Tucson and the Cerro Tololo Inter-American Observatory in Chile, and he was a visiting professor at institutions including Harvard University and the College of William and Mary.

Dr. Peery was once asked whether his focus on the heavens came at the expense of addressing vital issues closer to home.

"I've engaged in my share of political activism," he replied. "But I believe that studying astronomy can change the way we view our human existence. . . . The very reason we have universities is to develop a larger sense of what it is to be alive, and that's very much what I've been doing."

Benjamin Franklin Peery was born in St. Joseph, Mo., and grew up in white communities in rural Minnesota.

"I grew up in three small towns," he once said, "and in every one of them we were the colored family."

He served in the Army during World War II - "the most segregated period of my life," he later said. After completing his military service, he received a physics degree in 1949 from the University of Minnesota.

He went on to receive a master's degree in physics from Fisk University in Nashville and continued graduate work at the University of Michigan, where he became one of the first African Americans in the nation to receive a doctorate in astronomy.

Dr. Peery was a member of the International Astronomical Union and the Astronomical Society of the Pacific. He was also a member of Paint Branch Unitarian Universalist Church in Adelphi.

Survivors include his wife of 56 years, Darnelle Macklin Peery of Silver Spring; a daughter, Yvany B. Peery of Silver Spring; and six brothers.

In 1991, Dr. Peery appeared in an episode of "The Astronomers," a 1991 PBS documentary series.

"The whole Earth and everything in it," he said in the last seconds of the program, "is the product of stardust."