Theodor Jacobsen, 102; Professor, Astronomer Studied Variable Stars

Theodor Jacobsen, 102, a former University of Washington astronomer who studied the pulsation of variable stars for 70 years, died July 17 in Seattle of old age.

Jacobsen, the sole member of the school’s astronomy department during much of his tenure, retired to emeritus status in 1971 but remained active in the field.

He completed his final book, “Planetary Systems From the Ancient Greeks to Kepler,” published by the University of Washington Press, at 98. The book uses modern mathematics to explain how the theories of astronomers through the centuries were derived.

A native of Nyborg, Denmark, Jacobsen found the fascination of his life at age 7 when his parents gave him a telescope with a 2-inch lens set into a paper tube.

The family immigrated to the United States during World War I in 1917. Jacobsen completed undergraduate studies at Stanford University, earned a doctorate at UC Berkeley and, in 1928, joined the Washington faculty

He was the only member of the astronomy faculty until 1965. Since then the department has grown to more than 30 faculty and researchers.