The Arizona Daily Star's Centennial salute to science in Arizona runs all summer. Each day, for 100 days, we'll record a milestone in the state's scientific history.
The original small dome on the University of Arizona campus, built with a donation from Oracle resident Lavinia Steward, was dedicated in 1923. It housed a 36-inch reflecting telescope - at the time, one of the largest in the world.
The observatory's first director was A.E. Douglass, who came to teach physics and founded an astronomy program at the University of Arizona after parting ways with Percival Lowell in Flagstaff.
The telescope was moved to Kitt Peak in 1963.
Steward Observatory, meanwhile, has grown into one of the largest in the world with optical, infrared and radio facilities on Mount Lemmon and Kitt Peak and partnerships in large telescopes on Mount Graham, Mount Hopkins and in Chile.
At sites on or near campus, it builds the world's largest telescope mirrors and cameras, in addition to instruments for NASA space programs.
Steward Observatory and the UA Astronomy Department now represent a $50 million to $80 million annual enterprise, and employ more than 400 people.
The Steward Observatory dome, surrounded now by the multistory brick buildings of the campus that grew around it, is still used for public viewing on several nights throughout the year, in conjunction with the department's lecture series.