Built in 1932 following bequest from William J. McDonald, amateur astronomer. On 6,791-foot peak of Mount Locke. Site selected because of clear air, high ratio of cloudless nights, distance from concentrations of artificial lights, and dust- and radiation-filtering growths of shrubs and timber. Original instrument was 82-inch reflector; 107-inch reflector is in larger dome.
The Hobby-Eberly Telescope (HET), the third largest in the world, was designed to specialize in spectroscopy, the technique astronomers use to break down light into its component wavelengths. The telescope was built and is owned by a consortium of five universities: The Univ. of Texas at Austin; The Pennsylvania State Univ.; Stanford Univ.; Ludwig-Maximilians Univ. of Munich, Germany; and Georg-August Univ. of Goettingen, Germany. The HET is connected to the George T. Abell Gallery. Interpretive programs in the Abell Gallery highlight the HET's design and purpose. Free self-guided tour for the Abell Gallery. A more extensive guided tour of the HET is available with admission fee. For those driving recreation vehicles, limited-seating shuttle service is available from the Visitors Center for guided tours only.
The Visitors Center, at the foot of Mount Locke, is open daily 9 a.m.–5 p.m. Solar viewings are presented daily at 11 a.m. and 2 p.m. General admission fee required for the solar viewing and entrance to new Decoding Starlight exhibit at the Visitors Center. Guided tours (fee) of the large telescopes are at 11:30 a.m. and 2:30 p.m. daily and also include the solar viewing and exhibit admission. Each Tue., Fri. and Sat. evening, the center conducts "Star Parties" for the general public, with viewing of stars and planets through telescopes set up by the observatory. An alternate program will be conducted in the event of inclement weather. Closed Thanksgiving, Christmas and New Year's Day. The observatory is 16 miles northwest via Texas 118, Spur 78.
Once a month, visitors can view celestial objects through 107-inch telescope by making reservation with visitor center. (Very popular and sometimes booked months in advance.) Fee charged for large telescope viewing. 432/426-3640. McdonaldObservatory.org.