McDonald Observatory unveils $40 million upgrade
By JOHN DANIEL GARCIA
McDONALD OBSERVATORY – The Hobby-Eberly Telescope (HET) at McDonald Observatory is back in business after a nine-year, $40 million upgrade, which has, in essence, turned the 10-meter telescope into a brand new instrument for research into theoretical “dark energy.”
The telescope, Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) project manager Herman Kriel said at a Saturday press conference, has been upgraded to widen the telescope’s field of vision to 22 arcminutes and has been outfitted with new Visible Integral-field Replicable Unit Spectrograph (VIRUS) units, making the HET the most powerful spectrograph in the world.
The VIRUS units, he explained, are the first spectrographs that can be mass-produced. The telescope will contain a total of 80 VIRUS units, each of which holds 448 fiber optic cables that collect the data, giving the telescope’s spectography cameras a 633 megapixel rating. For comparison, cell phone cameras produce up to 16 megapixel images.
Spectrographs work by separating the light of an object and turning that light into a frequency spectrum, which can be read to record the distance and size of the object.
The 29-ton telescope with all VIRUS units running, Kriel said, will be cooled by liquid nitrogen, for which an 11,000-gallon tank was added to the observatory campus. The telescope will require about 6,000 gallons of liquid nitrogen per month to keep the telescope functional.
As of now, the telescope has been outfitted with 16 of the 78 VIRUS units that are located on each side of the HET, with 16 more to be installed in May and an early 2018 estimation for the full load. Two additional units will also be operational, though they will not be on the “saddlebag” enclosures that have been built on the telescope.
“It’s a completely new telescope,” said Kriel in his thick South African accent. “With the new tracker and wide-field corrector and instrumentation, this is a much more powerful telescope that we had.”
The upgrade was made to accommodate the HETDEX project, which according to U.T. professor of astrophysics Karl Gebhardt, is an attempt to verify the theory that a force repeals objects in space, causing the universe to expand.
The term “dark energy,” he said, is a relatively new term that was added to the equation of the traveling of light after computations failed.
Scientists who expected to find that the expansion of the universe has slowed, he said, were surprised to find that the expansion had actually accelerated.
“’Dark energy” represents the ignorance of what it is,” he said, adding that you can calculate gravitational force and space, known as the cosmological constant. “As we walk away [from each other], gravity is decreasing and space is increasing.”
The force that repeals objects, he explained, is the theoretical dark energy.
To show the theory, Gebhardt pointed to fingerprints, as though the shape of the grooves remain the same throughout one’s lifespan, the spaces in between expand.
The experiments in dark energy, he explained, includes the use of spectography to “make a map of the universe,” with the spectrographs allowing scientists to pinpoint the distance of celestial bodies.
When the experiment is completed in about 3 ½ years, he said, the scientists should have about 2.9 million images from HET, each of which will be studied by the human eye.
“The eye is a remarkable tool in finding very low-level structure in a noise,” he said.
The HETDEX will be able to produce data for the 8 billion – 11 billion year range, which the astrophysicist said will give scientists “a pattern for how galaxies [have been] distributed” from the 13.7 billion years since the big bang.
For Gebhardt, the investment of time and funds into the project – and astrophysics in general – not only advances technological breakthrough, but also helps understand the position of humanity in the universe.
“Inventions have come out of this like Wi-Fi and the internet. Astrology works to push technology a little faster, but why I do this is because astronomy is out of this world,” he said. “It gives us a better appreciation for who we are and where we are in the universe. There are not a lot of sciences that can do this.”
The HET, Penn State professor and co-designer of the telescope Larry Ramsey said, saw first light in 1997, three years after the groundbreaking for the telescope.
The telescope was commissioned in 2002, when astronomers began conducting early experiments.
The telescope saw 11 years of experimentation before shutting down for the upgrades in 2013, resulting in around 300 published papers across a number of experimentations.
The HET, he said, was built for around $13.5 million, which was far less than other 8-meter class telescopes, which cost between $40 – $100 million due to engineering breakthroughs.
“We built an optical telescope that was unlike anything that ever existed,” he said of the telescope, which remains one of the largest spectrographic telescopes in the world.
The fact that the telescope is made of a consortium of universities using private funds, McDonald Observatory director Taft Armandroff added, has allowed for scientists to spend more time on specific projects, as they don’t have to answer to government or tax-payers.
“We have an alliance of support, and the purpose for that is to have a wide range of science,” he said. “We’re able to make bigger bets.”
The telescope and its advancements, he added, have been very important to the field.
“This will be in the textbooks 200 years from now,” he said.