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  • richardmitnick 11:48 am on April 13, 2017 Permalink | Reply
    Tags: , , , , HETDEX, Hobby-Eberly Telescope Updated, , VIRUS spectrographs   

    From U Texas at Austin: Hobby-Eberly Telescope Updated 

    U Texas Austin bloc

    University of Texas at Austin

    1
    Hobby-Eberly Telescope. 2011-05-10 | Max Planck Institute for extraterrestrial physics

    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 10 meter effective aperture places it among the world’s five largest telescopes.

    Work is underway to modify the telescope for the upcoming Dark Energy Experiment (HETDEX). The addition of 150 integral field spectrographs (VIRUS), 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.

    2
    Artist’s concept of the upgraded Hobby-Eberly Telescope. The VIRUS spectrographs are contained in the curved gray “saddlebags” on the side of the telescope.

    Unique and Powerful Survey Instrument

    The deployment of the Visible Integral-field Replicable Unit Spectrograph (VIRUS), for the HETDEX project, will transform the HET into a powerful survey instrument like no other in astronomy, placing 35,000 fibers on the sky, each capable of collecting a distinct spectrum, with every exposure. VIRUS is scheduled to begin science operations in 2017.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Texas Arlington Campus

    In 1839, the Congress of the Republic of Texas ordered that a site be set aside to meet the state’s higher education needs. After a series of delays over the next several decades, the state legislature reinvigorated the project in 1876, calling for the establishment of a “university of the first class.” Austin was selected as the site for the new university in 1881, and construction began on the original Main Building in November 1882. Less than one year later, on Sept. 15, 1883, The University of Texas at Austin opened with one building, eight professors, one proctor, and 221 students — and a mission to change the world. Today, UT Austin is a world-renowned higher education, research, and public service institution serving more than 51,000 students annually through 18 top-ranked colleges and schools.

     
  • richardmitnick 2:39 pm on March 24, 2017 Permalink | Reply
    Tags: , , , , , HETDEX, , ,   

    From WIRED: “Astronomers Don’t Point This Telescope—The Telescope Points Them” 

    Wired logo

    WIRED

    03.23.17
    Sarah Scoles

    1
    U Texas Austin McDonald Observatory Hobby-Eberly Telescope

    The hills of West Texas rise in waves around the Hobby-Eberly Telescope, a powerful instrument encased in a dome that looks like the Epcot ball. Soon, it will become more powerful still: Scientists recently primed the telescope to find evidence of dark energy in the early universe, prying open its eye so it can see and process a wide swath of sky. On April 8, scientists will dedicate the new telescope, capping off the $40 million upgrade and beginning the real work.

    The dark energy experiment, called Hetdex, isn’t how astronomy has traditionally been done. In the classical model, a lone astronomer goes to a mountaintop and solemnly points a telescope at one predetermined object. But Hetdex won’t look for any objects in particular; it will just scan the sky and churn petabytes of the resulting data through a silicon visual cortex. That’s only possible because of today’s steroidal computers, which let scientists analyze, store, and send such massive quantities of data.

    “Dark energy is not only terribly important for astronomy, it’s the central problem for physics. It’s been the bone in our throat for a long time.”

    Steven Weinberg
    Nobel Laureate
    University of Texas at Austin

    The hope is so-called blind surveys like this one will find stuff astronomers never even knew to look for. In this realm, computers take over curation of the sky, telling astronomers what is interesting and worthy of further study, rather than the other way around. These wide-eyed projects are becoming a standard part of astronomers’ arsenal, and the greatest part about them is that their best discoveries are still totally TBD.

    Big Sky Country

    To understand dark energy—that mysterious stuff that pulls the taffy of spacetime—the Hetdex team needed Hobby-Eberly to study one million galaxies 9-11 billion light-years away as they fly away from Earth. To get that many galaxies in a reasonable amount of time, they broadened the view of its 91 tessellated stop-sign-shaped mirrors by 100. They also created an instrument called Virus, with 35,000 optical fibers that send the light from the universe to a spectrograph, which splits it up into constituent wavelengths. All that data can determine both how far away a galaxy is and how fast it’s traveling away from Earth.

    But when a telescope takes a ton of data down from the sky, scientists can also uncover the unexpected. Hetdex’s astronomers will find more than just the stretch marks of dark energy. They’ll discover things about supermassive black holes, star formation, dark matter, and the ages of stars in nearby galaxies.

    The classical method still has advantages; if you know exactly what you want to look at, you write up a nice proposal to Hubble and explain why a fixed gaze at the Whirlpool Galaxy would yield significant results. “But what you see is what you get,” says astronomer Douglas Hudgins. “This is an object, and the science of that object is what you’re stuck with.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 5:16 pm on March 31, 2016 Permalink | Reply
    Tags: , , HETDEX,   

    From U Texas- “Karl Gebhardt: Mapping the Universe” 

    U Texas Austin bloc

    University of Texas at Austin

    1

    “With dark energy we know nothing. It may not be dark and it may not be energy. It’s the phrase we use to explain our ignorance.” —Karl Gebhardt

    Karl Gebhardt is an expert in trying to measure the currently un-measureable. The Herman and Joan Suit Professor of Astrophysics in the Department of Astronomy has spent most of his career focused on understanding the role that black holes play in the formation of a galaxy. Now he is helping to lead a new scientific revolution: the quest to understand dark energy, a mysterious force that makes up 70 percent of the matter and energy in the universe.

    U Texas McDonald Observatory Hobby-Eberle 9.1 meter Telescope
    U Texas McDonald Observatory Hobby-Eberle 9.1 meter Telescope

    What do we know about dark energy?

    We know nothing. We are very ignorant. All we know is that the universe is expanding at an accelerated rate. We have an idea of what the universe is and how all this material interacts. We believe we understand the laws of gravity. We believe we understand how light evolves over time. But when we go out and try and measure how the universe expands, we find that it is expanding significantly faster than we thought.

    The phrase “dark energy” is indicative of our misunderstanding of how the universe expands over time. Dark energy may not be dark and it may not be energy — it’s the phrase we use to explain our ignorance.

    How do you research something we know nothing or very little about?

    Throughout my career I have been focusing on black holes and dark matter and dark energy. These are all things we cannot see. The only way to measure them is to see their effect on things we can see, like stars, gas or galaxies. With dark energy, for example, we see how the galaxies are distributed and move. From their location and motions we infer what caused them to be in that pattern. You use what you know to infer how it came into that configuration.

    What is the cocktail-party explanation for how you measure the expansion of the universe?

    Measuring the expansion rate is really not that hard. When the galaxies are expanding they have a “fingerprint.” Over time, as you grow, the space between each line in your fingerprint expands. You can measure your expansion rate from when you were a little baby just by seeing how far away the lines are in your finger. That’s your expansion rate.

    For the universe, you look at how galaxies are distributed at various times. You find that pattern and you watch that pattern expand. To capture that pattern we need to make a giant map of the universe.

    How do you make a map of the universe?

    My idea is a project called HETDEX — Hobby-Eberly Telescope Dark Energy Experiment. HETDEX is going to measure the position and velocities of about a million galaxies about 10 billion years ago. No one in astronomy has done this before, and the galaxies we are looking at are very faint. So we took one of the biggest telescopes in the world and put on a suite of 150 spectragraphs. And we are going to just sit there and take shots over shots of sky to make a map of the cosmos. It will take about three or four years.

    How do you gauge success in a theoretical field? What would it mean to “understand” dark energy?

    A major problem in science is knowing when you are done. Science is really an effort to exclude possibilities. You never really get to the answer.

    For example, we don’t understand how gravity works yet! That blows my mind. Newton had his ideas. Einstein came in and modified that. And we know Einstein needs modification as well. Dark energy may be yet another kind of hook towards understanding what gravity is doing. So we don’t ever get to a final answer. It just builds up over time. I hope HETDEX is going to be a big advance. We have designed it that way, but you just don’t know what you are going to get.

    What is your ideal discovery?

    That we would discover a universe that is not conforming to our standard model. My expectation is we are going to find something that is unexpected.

    Wait, your ideal discovery is not an answer, but more problems?

    [Laughing] Not exactly. I’m looking for something out of the box here. When we built HETDEX we thought long and hard about just trying to do better measurement in the nearby universe. Or, should we focus instead at a time that no one has looked at before. The current theory says you might not find a lot if you look that far back in time. And we said, we have to look. Let’s look at a new epoch and see if we can find a differential effect. I think that’s where you learn the most.

    What roles do innovation and creativity play in your research?

    Innovation and creativity are huge. That’s what it’s about. When you have a problem like dark energy — and the problem is you don’t have theoretical guidance — it is so hard to design an experiment to observe something that you don’t know what it is. We decided to be creative by looking at a new time in the universe in a way it hasn’t been looked at before.

    What do you want people to understand about dark energy?

    We are trying to understand where the universe came from and where it is going. That’s what I like to drive home when I teach a class or talk to the public: Understanding where you stand in relation to the cosmos. It’s very hard to predict if there will be any practical implications in this. Astronomy is just about as out of this world as you can imagine. But just to appreciate our ability as a collective species to understand where we came from and where we are going. It gives a sense of our being. That’s what I love. And that’s what makes us special.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    U Texas Arlington Campus

    In 1839, the Congress of the Republic of Texas ordered that a site be set aside to meet the state’s higher education needs. After a series of delays over the next several decades, the state legislature reinvigorated the project in 1876, calling for the establishment of a “university of the first class.” Austin was selected as the site for the new university in 1881, and construction began on the original Main Building in November 1882. Less than one year later, on Sept. 15, 1883, The University of Texas at Austin opened with one building, eight professors, one proctor, and 221 students — and a mission to change the world. Today, UT Austin is a world-renowned higher education, research, and public service institution serving more than 51,000 students annually through 18 top-ranked colleges and schools.

     
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