From the Board of Visitors Executive Committee
August 12, 2013: HETDEX Installation Begins
After nearly a decade of planning, detailed engineering, construction, and testing, the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) entered its installation phase on August 12, 2013.
McDonald Observatory Director David Lambert says, “August 12 sees the culmination of several years of intense effort in planning and construction. Thanks to the support we have received and our team’s dedication, HETDEX will unravel the mystery that is dark energy, and it will provide the world’s best tool for answering numerous other questions in astrophysics.”
The Universe’s Greatest Mystery
Only discovered in the late 1990s, “dark energy” dominates our Universe, making up an estimated 73 percent of all its matter and energy and causing the expansion of the Universe to accelerate (when it should be slowing down). By comparison, what we call “normal” matter — everything made of atoms — constitutes only four percent. Beyond its existence and its cosmic importance, almost nothing is known about the nature of dark energy — and, by worldwide consensus, it is identified as the single most important mystery in all of the sciences. Leaders of the two teams that made the initial discovery of dark energy were awarded the Nobel Prize in Physics in 2011. Many projects have been proposed to move knowledge of dark energy forward, and two competing ground-based projects are under way. The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) stands apart.
HETDEX’s Unique Contribution
HETDEX will find and map up to one million (very early) galaxies that lie between 10 and 12 billion light years away. Competing projects are studying more-recent galaxies, some five to six billion light years distant. Texas scientists, by comparing the distribution of early galaxies that HETDEX finds with patterns in the Cosmic Microwave Background Radiation, will provide unique insights into whether dark energy has evolved over time — a crucial parameter. Additionally, HETDEX can provide a test of whether, to a few tenths of a percent, the Universe’s geometry is curved or flat. In fact, competing projects won’t, on their own, be able to disentangle the possible effects of dark energy and those of curvature in the Universe. They will need HETDEX’s observations to reach their ultimate goals (and their findings will complement the discoveries that HETDEX will make).
HETDEX begins with the Hobby-Eberly Telescope (HET), one of the world’s largest. The improvements to the HET for HETDEX include the Wide Field Upgrade, which comprises the Wide Field Corrector (a set of four new mirrors that will increase the telescope’s field of view from 4 arc minutes to 22 arc minutes — half the size of the full Moon); a larger suite of precision instruments called the Prime Focus Instrument Package; a new, much stronger Tracker. The improvements also include the 150 spectrographs that make up the VIRUS instrument, fed by 33,000 fibers from the telescope. Once these components are installed, between now and Summer 2014, the HETDEX team will begin the three-year survey that will reveal—better than any other project— key secrets of dark energy, the entity that dominates our Universe.
HETDEX, with a budget of $37.5 million, is the most complex and technically challenging project ever undertaken by The University of Texas at Austin McDonald Observatory. It would not have been possible without the partnership of private donors —both individuals and foundations — along with U.S. government agencies, the State of Texas, The University of Texas at Austin, and a team of international institutions that have joined in to help HETDEX make scientific history.
- $37 million raised from multiple sources.
- Planning and engineering of Tracker and other components of the Wide Field Upgrade systems completed
- Parts procured for all major systems
- New Tracker hardware and software completed at The University of Texas at Austin’s Center for Electromechanics.
- New Prime Focus Instrument Package fully assembled, passes all tests.
- Four mirrors for the new Wide Field Corrector created, figured, coated, and integrated at the University of Arizona; alignment and final testing are ongoing.
- VIRUS spectrograph assembly and testing are on schedule at The University of Texas at Austin, Texas A&M University, and at German partner institutions.
- External Readiness Review by experts from Harvard and the University of Virginia results in HET Board’s approval to start the upgrade.
Key Upcoming Milestones
- Shut down HET
- Finish removing old Tracker
- Start new Tracker installation
- Wide Field Corrector delivered and tested on-site
- Prime Focus Instrument Package completed
- New Tracker installation completed
- Install Wide Field Corrector
- Start Prime Focus Instrument Package installation
- First light
- Rebuilt Hobby-Eberly Telescope commissioned
- VIRUS commissioned
HETDEX is a collaboration led by The University of Texas at Austin McDonald Observatory, with partners including Pennsylvania State University, Texas A&M University, Universitats-Sternwärte Munich, Leibniz Institute für Astrophysics (AIP), Max-Planck-Institut für Extraterrestrische Physik, Institut für Astrophysik Göttingen, and the University of Oxford. Financial support is provided by the State of Texas, the United States Air Force, the National Science Foundation, and the generous contributions of many private foundations and individuals.