HET Overview

The Project

The Hobby-Eberly Telescope ( HETHobby-Eberly Telescope. ) is a 9.2 meter telescope built by an international collaboration among

The HET is named in honor of its principal benefactors, Lt. Governor William P. Hobby, Jr., of Texas and Robert E. Eberly of Pennsylvania. The HET employs a unique design that marks a fundamental departure from the usual paradigm for building large optical telescopes. The engineering approach adopted makes the HET a quality instrument that maximizes the scientific research capability and minimizes cost. The HET was built at the University of Texas McDonald Observatory near Ft. Davis, Texas for a cost of $15 million, not including instruments.

The HET is located at:

W 104 00 53.0
N 30 40 53.2
2026 meters above the geoid
on the WGS84 system

First light was achieved December 10, 1996, and the telescope was dedicated October 8, 1997. Telescope commissioning began September 6, 1997 and ended October 1, 1999.

The HET is currently in its "full operations" phase. In this phase, research operation is scheduled for the full lunation with instrument commissioning and telescope engineering being scheduled as needed. A Low Resolution Spectrograph (at prime focus), a High Resolution Spectrograph (fiber-fed) and a Medium Resolution Spectrograph (fiber-fed) are fully operational.

The design feature central to the HET is specialization: the HET is tailored for spectroscopy, in particular, fiber-coupled spectroscopy. By limiting observational flexibility, extremely cost-effective technical solutions are possible and these have been implemented in the HET. Specifications include a segmented, spherical primary mirror whose optical axis is tipped 35° from zenith. The primary mirror is mounted on a structure which turns 360° in azimuth. The angle of the primary mirror with respect to gravity is thus constant, resulting in large cost savings in the mirror and mirror support systems. During an observation the telescope is fixed in azimuth and objects are tracked at the prime focus. Mounted at prime focus are a four-element, all-reflecting spherical aberration corrector, acquisition and guiding cameras, and the Low Resolution Spectrograph. HET reflecting surfaces utilize aluminum coatings but work on overcoated surfaces is ongoing.

This Overview is divided into several categories:

A) The Telescope