Harlan J. Smith Telescope, Research telescope at McDonald Observatory in Davis Mountains, Texas.

The Harlan J. Smith Telescope is a major research instrument at McDonald Observatory in the Davis Mountains of Texas. With its 2.7-meter primary mirror and weighing 160 tons, the telescope sits inside a 23-meter dome that protects this sensitive equipment from the elements.

The telescope began operations in 1968 and was then the third largest optical reflecting telescope in the world. It was developed with NASA support for astronomical observation and exploration purposes.

The McDonald Observatory facility welcomes researchers and astronomers from the University of Texas at Austin to conduct studies of stars and distant galaxies.

The Harlan J. Smith Telescope stands on Mount Locke in the Davis Mountains of west Texas, reached by winding mountain roads; the site is remote and the weather can change quickly. The 2.7-meter instrument is a working research telescope, so check visiting arrangements with McDonald Observatory before travelling.

In February 1970 a newly hired worker brought a handgun into the observatory, shot at his supervisor and then fired the remaining rounds into the primary mirror. The holes cut the 107-inch aperture to the equivalent of about 106 inches, roughly 2.5 centimetres less light-gathering area, yet image quality was unaffected.