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

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  • richardmitnick 2:16 pm on November 9, 2015 Permalink | Reply
    Tags: , , , , U Texas McDonald Observatory Hobby-Eberle 9.1 meter telescope   

    From ars technica: “Finally some answers on dark energy, the mysterious master of the Universe” 

    Ars Technica
    ars technica

    Nov 5, 2015
    Eric Berger

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

    Unless you’re an astrophysicist, you probably don’t sit around thinking about dark energy all that often. That’s understandable, as dark energy doesn’t really affect anyone’s life. But when you stop to ponder dark energy, it’s really rather remarkable. This mysterious force, which makes up the bulk of the Universe but was only discovered 17 years ago, somehow is blasting the vast cosmos apart at ever-increasing rates.

    Astrophysicists do sit around and think about dark energy a lot. And they’re desperate for more information about it as, right now, they have essentially two data points. One shows the Universe in its infancy, at 380,000 years old, thanks to observations of the cosmic microwave background radiation. And by pointing their telescopes into the sky and looking about, they can measure the present expansion rate of the Universe.

    But astronomers would desperately like to know what happened in between the Big Bang and now. Is dark energy constant, or is it accelerating? Or, more crazily still, might it be about to undergo some kind of phase change and turn everything into ice, as ice-nine did in Kurt Vonnegut’s novel Cat’s Cradle? Probably not, but really, no one knows.

    The Plan

    Fortunately astronomers in West Texas have a $42 million plan to use the world’s fourth largest optical telescope to get some answers. Until now, the 9-meter Hobby-Eberly telescope at McDonald Observatory has excelled at observing very distant objects, but this has necessitated a narrow field of view. However, with a clever new optical system, astronomers have expanded the telescope’s field of view by a factor of 120, to nearly the size of a full Moon. The next step is to build a suite of spectrographs and, using 34,000 optical fibers, wire them into the focal plane of the telescope.

    “We’re going to make this 3-D map of the Universe,” Karl Gebhardt, a professor of astronomy at the University of Texas at Austin, told Ars. “On this giant map, for every image that we take, we’ll get that many spectra. No other telescope can touch this kind of information.”

    With this detailed information about the location and age of objects in the sky, astronomers hope to gain an understanding of how dark energy affected the expansion rate of the Universe 5 billion to 10 billion years ago. There are many theories about what dark energy might be and how the expansion rate has changed over time. Those theories make predictions that can now be tested with actual data.

    In Texas, there’s a fierce sporting rivalry between the Longhorns in Austin and Texas A&M Aggies in College Station. But in the field of astronomy and astrophysics the two universities have worked closely together. And perhaps no one is more excited than A&M’s Nick Suntzeff about the new data that will come down over the next four years from the Hobby-Eberly telescope.

    Suntzeff is most well known for co-founding the High-Z Supernova Search Team along with Brian Schmidt, one of two research groups that discovered dark energy in 1998. This startling observation that the expansion rate of the Universe was in fact accelerating upended physicists’ understanding of the cosmos. They continue to grapple with understanding the mysterious force—hence the enigmatic appellation dark energy—that could be causing this acceleration.

    Dawn of the cosmos

    When scientists observe quantum mechanics, they see tiny energy fluctuations. They think these same fluctuations occurred at the very dawn of the Universe, Suntzeff explained to Ars. And as the early Universe expanded, so did these fluctuations. Then, at about 1 second, when the temperature of the Universe was about 10 billion degrees Kelvin, these fluctuations were essentially imprinted onto dark matter. From then on, this dark matter (whatever it actually is) responded only to the force of gravity.

    Meanwhile, normal matter and light were also filling the Universe, and they were more strongly affected by electromagnetism than gravity. As the Universe expanded, this light and matter rippled outward at the speed of sound. Then, at 380,000 years, Suntzeff said these sound waves “froze,” leaving the cosmic microwave background.

    These ripples, frozen with respect to one another, expanded outward as the Universe likewise grew. They can still be faintly seen today—many galaxies are spaced apart by about 500 million light years, the size of the largest ripples. But what happened between this freezing long ago, and what astronomers see today, is a mystery.

    The Texas experiment will allow astronomers to fill in some of that gap. They should be able to tease apart the two forces acting upon the expansion of the Universe. There’s the gravitational clumping, due to dark matter, which is holding back expansion. Then there’s the acceleration due to dark energy. Because the Universe’s expansion rate is now accelerating, dark energy appears to be dominating now. But is it constant? And when did it overtake dark matter’s gravitational pull?

    “I like to think of it sort of as a flag,” Suntzeff said. “We don’t see the wind, but we know the strength of the wind by the way the flag ripples in the breeze. The same with the ripples. We don’t see dark energy and dark matter, but we see how they push and pull the ripples over time, and therefore we can measure their strengths over time.”
    The universe’s end?

    Funding for the $42 million experiment at McDonald Observatory, called HETDEX for Hobby-Eberly Telescope Dark Energy Experiment, will come from three different sources: one-third from the state of Texas, one-third from the federal government, and a third from private foundations.

    The telescope is in the Davis Mountains of West Texas, which provide some of the darkest and clearest skies in the continental United States. The upgraded version took its first image on July 29. Completing the experiment will take three or four years, but astronomers expect to have a pretty good idea about their findings within the first year.

    If dark energy is constant, then our Universe has a dark, lonely future, as most of what we can now observe will eventually disappear over the horizon at speeds faster than that of light. But if dark energy changes over time, then it is hard to know what will happen, Suntzeff said. One unlikely scenario—among many, he said—is a phase transition. Dark energy might go through some kind of catalytic change that would propagate through the Universe. Then it might be game over, which would be a nice thing to know about in advance.

    Or perhaps not.

    See the full article here .

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    Ars Technica was founded in 1998 when Founder & Editor-in-Chief Ken Fisher announced his plans for starting a publication devoted to technology that would cater to what he called “alpha geeks”: technologists and IT professionals. Ken’s vision was to build a publication with a simple editorial mission: be “technically savvy, up-to-date, and more fun” than what was currently popular in the space. In the ensuing years, with formidable contributions by a unique editorial staff, Ars Technica became a trusted source for technology news, tech policy analysis, breakdowns of the latest scientific advancements, gadget reviews, software, hardware, and nearly everything else found in between layers of silicon.

    Ars Technica innovates by listening to its core readership. Readers have come to demand devotedness to accuracy and integrity, flanked by a willingness to leave each day’s meaningless, click-bait fodder by the wayside. The result is something unique: the unparalleled marriage of breadth and depth in technology journalism. By 2001, Ars Technica was regularly producing news reports, op-eds, and the like, but the company stood out from the competition by regularly providing long thought-pieces and in-depth explainers.

    And thanks to its readership, Ars Technica also accomplished a number of industry leading moves. In 2001, Ars launched a digital subscription service when such things were non-existent for digital media. Ars was also the first IT publication to begin covering the resurgence of Apple, and the first to draw analytical and cultural ties between the world of high technology and gaming. Ars was also first to begin selling its long form content in digitally distributable forms, such as PDFs and eventually eBooks (again, starting in 2001).

     
  • richardmitnick 11:33 am on November 3, 2015 Permalink | Reply
    Tags: , , U Texas McDonald Observatory Hobby-Eberle 9.1 meter telescope   

    From U Texas McDonald Observatory: “Upgraded Hobby-Eberly Telescope Sees First Light” 

    McDonald Observatory bloc

    McDonald Observatory

    11.3.15

    After several years and a massive team effort, one of the world’s largest telescopes has opened its giant eye again. The Hobby–Eberly 9.1 meter Telescope (HET) at The McDonald Observatory has completed a $25 million upgrade and, now using more of its primary mirror, has achieved “first light” as the world’s third-largest optical telescope.

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

    “This upgrade makes HET the most powerful wide-field spectroscopic telescope worldwide, and we expect unique scientific discoveries from it,” observatory director Taft Armandroff said.

    The new HET made its first image on July 29. After extensive testing and fine-tuning, the team reports that image quality meets specifications— sharp enough to resolve features one mile across on the surface of the Moon (or in astronomical terms, a resolution of 0.9 arcseconds.)

    Spurred by the HET collaboration’s desire to do big science projects, including the forthcoming Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), the upgrade was a major undertaking that includes new optics, new mechanics, and new software. Today, HET is essentially a new telescope — only its primary mirror remains unchanged.

    What makes the new HET great? One major factor is the new Harold C. Simmons Dark Energy Optical System. This set of optics sits above the telescope’s main mirror, in the location usually occupied by a secondary mirror.

    McDonald Observatory chief scientist Phillip MacQueen designed the system. He explained that the Simmons System, informally called a “corrector,” is a complex set of optics, including four mirrors, that achieves two key tasks.

    First, it brings light from the primary mirror into sharp focus. Because HET’s primary mirror is spherical rather than parabolic, it does not focus light into a sharp image. To make sharp images, the primary mirror needs to feed light into a corrector before it is fed into scientific instruments.

    Second, the Simmons System allows good images from all parts of the telescope’s greatly enlarged field of view. The telescope’s field of view has increased by 120 times, and is 70% of the diameter of the full Moon (that is, 22 arcminutes or one-third of a degree).

    Research Associate Hanshin Lee managed a nearly seven-year process by The University of Arizona College of Optical Sciences to build and test the $6 million Simmons Optical System. It was a tough process to verify the optics and ensure they were set up properly.

    The work consisted of shaping the four mirrors (three 1-meter mirrors and one 0.25-meter mirror) to exacting specifications and testing those shapes, applying a specialized reflective coating, putting them together into a single package, and aligning them to high accuracy.

    Once the Simmons System was built, transporting the 2-ton assembly safely from Tucson to McDonald Observatory in West Texas was an undertaking fraught with danger. Its optics were so finely balanced that hitting any pothole could spell a problem. It made the 500-mile trip overnight, going 45 miles per hour, with a police escort and arrived May 28. Later testing verified that nothing had moved in the process — the optics were still aligned within a fraction of the width of a human hair.

    Lee said that throughout the difficult building and testing process “our staff was really fantastic in stepping up — while solving problems, they showed a lot of creativity and conviction that they could do it,” noting that it took many people with different talents to make the project a success.

    The Simmons System is “one of the most complex optical systems ever deployed in astronomy,” said Gary Hill, McDonald Observatory’s chief astronomer and principal investigator for HETDEX.

    Because it allows more of HET’s 10-meter by 11-meter mirror to be used, it makes HET a larger telescope. The mirror’s effective size has increased from 9.2 meters to 10 meters. This means that HET is now tied for the world’s third-largest optical telescope.

    The telescope also features a new tracker that supports the Simmons System (and a suite of instruments to ensure its alignment to extremely high precision) as it moves across the primary mirror tracking cosmic targets across the sky. The new tracker was built by The University of Texas at Austin Center for Electromechanics. A McDonald Observatory team led by Niv Drory developed HET’s entirely new control system.

    The upgraded telescope is now able to track and guide on cosmic targets. The next step for the HET team is to complete commissioning of the telescope. Then the team will move on to commissioning HET’s three new science instruments.

    Larry Ramsey, chairman of the HET Board of Directors and professor at Penn State, remarked, “The revitalized HET will contribute to many areas of science — not only the study of dark energy; but the nature of dark matter; the first stars in the universe; starburst galaxies; massive black holes; and to the discovery, confirmation, and characterization of extrasolar planets.”

    The Hobby-Eberly Telescope came online in 1997. It is a partnership between The University of Texas at Austin, The Pennsylvania State University, Georg-August-Universität Göttingen, and Ludwig-Maximilians-Universität München. The HET upgrade was funded by a combination of federal, state, and private sources.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    McDonald Observatory Campus

    Telescopes Are Windows To the Universe

    Astronomers use them to study everything from the asteroids and planets in our own solar system to galaxies billions of light-years away in space and time. Though they bring the mysteries of the universe to us, their workings are anything but mysterious. They gather and focus light from objects in the sky, so that it can be directed into an instrument attached to the telescope, and ultimately, studied in detail by a scientist. At McDonald Observatory, we have several telescopes, built at various times since the Observatory’s founding in the 1930s.

    Here is an introduction to the telescopes that McDonald Observatory astronomers use for their research:

    McDonald Observatory Hobby-Eberly Telescope
    Hobby-Eberly Telescope

    McDonald Observatory Harlan J Smith Telescope
    Harlan J. Smith Telescope

    McDonald Observatory Otto Struve telescope
    Otto Struve Telescope

    McDonald Observatory .8 meter telescope
    0.8-meter Telescope

    McDonald Observatory .9 meter telescope
    0.9-meter Telescope

    McDonald Observatory Rebecca Gale  Telescope Park
    Rebecca Gale Telescope Park

     
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