Hobby-Eberly Telescope

McDonald Observatory: Hobby-Eberly Telescope

Hobby-Eberly Telescope (HET), telescope that is one of the largest in the world, with a mirror measuring 11.1 by 9.8 metres (36.4 by 32.2 feet). It is located on Mount Fowlkes (2,024 metres [6,640 feet]) at the University of Texas at Austin’s McDonald Observatory near Fort Davis, Texas, U.S. The HET is named after Bill Hobby, lieutenant governor of Texas from 1973 to 1991, and Robert Eberly, a benefactor of Pennsylvania State University, which is a partner in the HET project. Fixed at an elevation angle of 55°, the HET moves only in azimuth and follows objects with a moving instrument package at the focal point of the telescope mirror. Although the fixed elevation means the HET cannot follow an object for more than 2.5 hours, it did cut the cost of building the telescope by 80 percent. The mirror is made up of 91 identical hexagonal segments. The HET is designed specifically for spectroscopy of astronomical objects. It has discovered several extrasolar planets. Construction on the HET began in 1994, and it made its first observations in 1996. Its design was later used as the basis for the Southern African Large Telescope. In addition to the University of Texas and Penn State, the HET is also funded by Stanford University, Ludwig Maximilians University in Munich, Ger., and Georg August University in Göttingen, Ger.