Otto Struve Telescope

The Otto Struve Telescope is a research instrument at McDonald Observatory in the Davis Mountains of Texas, equipped with a 2.1-meter primary mirror made of borosilicate glass. It uses electronic detectors and computer controls to enable observations of galaxies, stars, planets, and distant cosmic objects.

Upon its completion in 1939, this telescope ranked as the second-largest optical instrument in the world, surpassed only by the Hooker Telescope at Mount Wilson Observatory. It represents a turning point in American optical astronomy during the early 20th century.

The telescope bears the name of Otto Struve, the first director of McDonald Observatory who led the facility from 1932 to 1947 and shaped its scientific mission. His name honors his legacy in astronomy and makes the personal history of the observatory tangible for visitors.

The telescope is located in a remote mountainous region, so visitors should expect longer travel times and limited nearby services. The best time to visit is during clear, dark skies, which favor its use for observations.

This instrument played a key role in discovering Uranus' fifth moon Miranda and Neptune's moon Nereid, and identified carbon dioxide in Mars' atmosphere. These discoveries show how a single telescope shaped our understanding of the solar system.