HET Overview

Land Acknowledgement

The Hobby-Eberly Telescope ( HETHobby-Eberly Telescope. ) is a 10 meter class telescope run 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. Significant upgrades have continued to improve and adapt the telescope beyond its original construction.

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.

On August 19, 2013, the telescope went off-line for a very significant wide-field upgrade which included a new tracker and wide-field corrector. First light with the upgraded HET was obtained on July 29, 2015, and full science operations began in July 2016.

The HET is currently in its "full operations" phase. In this phase, research operation is scheduled for the full lunation with minimal instrument commissioning and telescope engineering being scheduled as needed. Currently three instruments are fully operational: the Low Resolution Spectrograph 2, the VIRUS spectrograph, and the Habitable zone Planet Finder. The High Resolution Spectrograph 2 is currently in progress.

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, and fiberoptic cables transmit light from the science target to the spectrographs. Mounted at prime focus are a four-element, all-reflecting spherical aberration corrector, acquisition cameras, and guiding/wavefront-sensing cameras. HET reflecting surfaces utilize aluminum coatings.

This Overview is divided into several categories:

A) The Telescope

  1. Technical Overview
  2. Object Observability
  3. Performance
B) Current Instruments
  1. LRS2
  2. VIRUS
  3. HPF
  4. HRS2 (in development)
C) Program Preparation and Monitoring
  1. Phase I
  2. Phase II
  3. Phase III
  4. Web Management System

    Last updated: Fri, 29 Dec 2023 01:47:32 +0000 stevenj


The Telescope

Technical Overview

Object Observability


Non-sidereal observations



LRS2 Summary

LRS2 Details

LRS2 Fiber Layout and Position Angle

LRS2 Throughput

LRS2 Observing details


VIRUS - Summary

VIRUS - Setting up on targets

VIRUS - Misc details

VIRUS - Throughput and sensitivity

VIRUS - low surface brightness sensitivity

VIRUS - Dithers, IFUs, Tiling

VIRUS - Tiling observations

Habitable Zone Planet Finder (HPF)

HPF Details

HPF Setting up on targets

HPF Throughput and Exposure Meter

HPF Data Reductions

HRS-2 (in development)

HRS-2 Summary

HRS-2 Details

HRS-2 configurations

HRS-2 exposure meter

HRS-2 Position Angle and Fiber layout

HRS-2 Throughput

Old Instruments

HRS - old

LRS - old

MRS - old

Program Preparation

Web Management System