McDonald Observatory, Astronomical observatory in the Davis Mountains, Jeff Davis County, Texas, United States

The McDonald Observatory sits in the Davis Mountains at an elevation of 2077 meters (6800 feet) and houses four research telescopes used for astronomical observations and scientific studies. The visitor center provides exhibition spaces and a viewing platform where you can see the telescope domes during daylight hours.

Texas banker William Johnson McDonald provided one million dollars in 1926 to fund the construction of this research facility for the University of Texas. The first telescopes were installed during the 1930s and the facility expanded its instruments over the following decades.

The observatory produces StarDate, a daily syndicated radio program of short astronomy segments that airs on National Public Radio and commercial stations, reaching about 400 affiliates. The name honors banker William Johnson McDonald, whose 1926 bequest of roughly $1 million founded the site. Evening programs use a 0.9 m telescope formerly reserved for research.

The road to reach the site climbs through winding mountain routes that may become impassable during bad weather. Reservations for evening telescope sessions should be made in advance as space is limited.

The Hobby-Eberly Telescope measures ten meters (33 feet) in diameter and ranks among the largest optical instruments in the world. Its design allows it to observe fixed zones of the sky, which reduces construction and operating costs compared to fully movable telescopes.