Andrew Ellicott Douglass arrived in Tucson in 1906 with a borrowed telescope and a dream. The astronomer, who would later pioneer dendrochronology and revolutionize climate science through tree-ring dating, took a position as Assistant Professor of Physics and Geography at the University of Arizona. Almost immediately, he began lobbying for a research-class telescope. He brought an 8-inch refractor on loan from Harvard College Observatory and started astronomical programs, but funding remained elusive. For a decade, Douglass petitioned the university, the Arizona Territorial Legislature, and later the State Legislature. Every effort failed. During those years, Douglass served as Head of the Department of Physics and Astronomy, Interim President of the university, and Dean of the College of Letters, Arts, and Sciences. His administrative duties grew, but the telescope remained a dream.

On October 18, 1916, University President Rufus B. von KleinSmid made a startling announcement: an anonymous donor had given $60,000 to buy a large telescope. The donor was Lavinia Steward, a wealthy widow living in Oracle, a small town in the Santa Catalina foothills north of Tucson. Mrs. Steward had an interest in astronomy and wanted to memorialize her late husband, Henry. Douglass immediately planned a 36-inch Newtonian reflector, contracting with the Warner and Swasey Company of Cleveland, Ohio to build it. Then America entered World War I. Warner and Swasey's war contracts took priority. Worse, the expertise in casting large telescope mirrors resided in Europe, now unreachable. Douglass had to find an American company willing to learn the art from scratch. After multiple failed attempts, the Spencer Lens Company of Buffalo, New York finally produced a successful 36-inch mirror. The telescope was formally dedicated on April 23, 1923.

Steward Observatory today operates telescopes across an empire of mountaintops. In southern Arizona alone, it manages Mount Graham International Observatory, Mount Lemmon Station, and Catalina Station on Mount Bigelow. It operates instruments at Kitt Peak National Observatory and the Fred Lawrence Whipple Observatory on Mount Hopkins. The Arizona Radio Observatory, a Steward sub-unit, runs a 10-meter millimeter-wavelength radio telescope on Mount Graham and a 12-meter dish on Kitt Peak. Beyond Arizona, Steward is a full member of the twin Magellan Telescopes at Las Campanas Observatory in northern Chile. The original observatory dome on the Tucson campus now houses the Ray White Jr. 21-inch telescope, used for public outreach and undergraduate education, a fitting echo of Lavinia Steward's original vision.

The Caris Mirror Lab has revolutionized how humanity builds telescopes. Its engineers pioneered spin-casting lightweight honeycomb mirrors in a rotating furnace, a technique that produces mirrors both lighter and more stable than solid glass. Stressed-lap polishing achieves surface precision measured in nanometers. The lab completed the second mirror for the Large Binocular Telescope in September 2005. It cast the 8.4-meter primary and tertiary mirror for what is now the Vera Rubin Observatory. Currently, the lab is fabricating seven 8.4-meter primary mirror segments for the Giant Magellan Telescope, a next-generation extremely large telescope. When complete, the GMT will have the resolving power to image planets around other stars.

Steward's influence reaches beyond any mountain. The Infrared Detector Laboratory built the Near Infrared Camera and Multi-Object Spectrometer for the Hubble Space Telescope and the Multiband Imaging Photometer for the Spitzer Space Telescope. For the James Webb Space Telescope, Steward constructed the Near-Infrared Camera, one of the observatory's primary instruments, and helped build the Mid-IR Instrument. When Webb's first images stunned the world in 2022, they came through Tucson-built technology. Other Steward research groups push boundaries in adaptive optics, imaging technology, and astrochemistry. The Center for Astronomical Adaptive Optics develops systems that remove atmospheric distortion from ground-based observations. All of this flows from a single act of generosity: a widow's gift, a scientist's persistence, and the clear Arizona skies that make Tucson one of the finest places on Earth to study the universe.