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

  1. Technical Overview
  2. Object Observability
  3. Performance
B) Instruments
  1. HRS
  2. MRS
  3. LRS
C) Program Preparation
  1. Phase I
  2. Phase II
D) Web Management System

E) Other HET Documentation

Last updated: Tue, 31 Jan 2012 10:11:38 -0600 sulu


The Telescope

Technical Overview

Object Observability




HRS Instrument Summary

HRS - Details

HRS Configurations

HRS Throughput

HRS Wavelength Calibration


MRS Instrument Summary

MRS Configurations

MRS Throughput

MRS Wavelength Calibration


LRS Instrument Summary

LRS Configurations

Multi-object Unit

LRS Throughput

LRS Spectral Resolution

LRS Wavelength Calibration

Visitor Filter Information

LRS Position Angles

Blind Offsetting

Guide Stars Limits

LRS Update from Gary Hill

Program Preparation

Web Management System

Other HET Documentation