The HET was designed and constructed with a unique objective: to gather a very
large amount of light, specifically for spectroscopy, at extremely low cost.
A fixed elevation-axis design, based on the radio telescope at Arecibo, and an
innovative system for tracking stars, contributed to an 80% reduction in initial costs compared to optical telescopes of similar size.
The primary mirror of the HET is the largest yet constructed, at 11.1 x 9.8 meters. At any given time during observations, only a
portion of the mirror is utilized. The HET's 9.2 meter effective aperture makes it currently the world's fourth largest optical telescope.
Work is underway to modify the telescope for the upcoming Dark Energy
Experiment. A new tracker, the massive framework on the top of the HET, will increase the telescope's field of view. The addition
of 150 integral field spectrographs, mounted to the sides of the main framework, will give the HET the ability to map the expansion
rate of the early universe, looking back in time billions of years, to measure how clusters of galaxies moved in relation to one another
as the universe evolved.
Wide Field Upgrade
The Wide Field Upgrade (WFU) is the first phase of the HETDEX retrofit.
Keep up with progress at
HET Blog, a forum where users
can post articles, comments and photos of the work. Time-lapse movies and live webcams are available at HETDEX WFU.
HET Observing Support
The pages of Mt. Fowlkes engineering staff, including policies and procedures, operations schedules, the problem
report management system, and other information.
The Trimester reports are prepared
by the HET Lead RA and include information about the seeing, weather, allocation of observations by partner, distribution
of objects and status of the equipment.
Bibliographic lists of HET science and technical publications.