Jerry Nelson, who conceived of the design for the segmented telescope, which allowed scientists to peer farther into the universe than ever before, died on June 10 at his home in Santa Cruz, Calif. He was 73.

His death was confirmed by his daughter, Alexandra Nelson, who said she did not know the cause.

Mr. Nelson’s designs were the basis for the twin telescopes at the W. M. Keck Observatory on Mauna Kea, a dormant volcano on the island of Hawaii. Astronomers have used those telescopes to help measure the giant black hole at the center of the Milky Way, and to find and confirm planetary bodies outside our solar system, including potentially habitable planets.

When the first Keck telescope was installed, in 1993, it was nearly twice as large as any other telescope, at 10 meters in diameter.

For decades, the size of telescopes seemed to have stalled with the roughly five-meter Hale Telescope at Palomar Mountain, Calif., built in 1949. (The Soviet Union constructed a roughly six-meter telescope in the Caucasus Mountains, but its performance never lived up to its size.)