In 1959. Jim Lattis MA’87, PhD’89, director of the UW Space Place, tells me that’s when the Astronomy Department relocated its offices and operations from Washburn Observatory, which had officially opened in 1881, into the newly completed east wing of Sterling Hall.
The upper floor of the Sterling Hall addition — the sixth floor, to be precise —had been designed specifically for the Astronomy Department. The largest dome on the roof level houses the department’s planetarium, and other enclosures hold three permanently mounted telescopes intended primarily for instructional uses.
Different instruments have been mounted there over the years. One of them, still in use today, is a famous antique telescope that predates even Washburn Observatory's historic 15.6-inch refractor. That telescope had once been part of the long-gone Student Observatory that sat next to Washburn Observatory, until about 1960, up on Observatory Hill.
Lattis notes that Sterling Hall’s east wing was recently renovated, and the Astronomy Department now occupies all floors of the east wing. The telescope mountings and domes are still there, as is the planetariumm, which is now accessible by elevator.