A next-generation experiment will create the largest 3D map of the universe and help Berkeley Lab scientists get a handle on dark energy.
For the past several years, scientists at the U.S. Department of Energy’s Lawrence Berkeley National Lab (Berkeley Lab) have been planning the construction of and developing technologies for a very special instrument that will create the most extensive three-dimensional map of the universe to date. Called DESI for Dark Energy Spectroscopic Instrument, this project will trace the growth history of the universe rather like the way you might track your child’s height with pencil marks climbing up a doorframe. But DESI will start from the present and work back into the past.
DESI will make a full 3D map pinpointing galaxies’ locations across the universe. The map, unprecedented in its size and scope, will allow scientists to test theories of dark energy, the mysterious force that appears to cause the accelerating expansion and stretching of the universe first discovered in observations of supernovae by groups led by Saul Perlmutter at Berkeley Lab and by Brian Schmidt, now at Australian National University, and Adam Riess, now at Johns Hopkins University. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
The Dark Energy Spectroscopic Instrument (DESI) will measure the effect of dark energy on the expansion of the universe. It will obtain optical spectra for tens of millions of galaxies and quasars, constructing a 3-dimensional map spanning the nearby universe to 10 billion light years.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
[img3="This screenshot, from an interactive Sky Viewer tool, shows a small region of the sky in the vicinity of the galaxy UGC 10041 imaged by the Dark Energy Camera Legacy Survey (DECaLS). Credit: Dustin Lang/University of Toronto"]http://1t2src2grpd01c037d42usfb.wpengin ... n-Lang.jpg[/img3][hr][/hr]
No need for hyperdrive: Scientists have released an “expansion pack” for a virtual tour of the universe that you can enjoy from the comfort of your own computer. The latest version of the publicly accessible images of the sky, which can be viewed using an interactive Sky Viewer tool, roughly doubles the size of the searchable universe from the project’s original release in May.
The images for this sky-mapping project, dubbed DECaLS (for Dark Energy Camera Legacy Survey) were taken by the 520-megapixel Dark Energy Survey Camera (DECam).
The scientific aim of DECaLS is to identify a select set of about 40 million galaxies and 2.5 million or more quasars—extremely luminous sources in the distant universe powered by massive black holes—that will be the focus of a ground-breaking project known as the Dark Energy Spectroscopic Instrument (DESI). ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Berkeley Lab-assembled ‘ProtoDESI’ to serve as model for planned array of 5,000 robots wielding fiber-optic cables.
Click to play embedded YouTube video.
A prototype system, designed as a test for a planned array of 5,000 galaxy-seeking robots, is taking shape at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab).
Dubbed ProtoDESI, the scaled-down, 10-robot system will help scientists achieve the pinpoint accuracy needed to home in on millions of galaxies, quasars and stars with the Dark Energy Spectroscopic Instrument (DESI) planned for the Mayall Telescope at Kitt Peak National Observatory near Tucson, Ariz. ProtoDESI will be installed on the Mayall Telescope this August and September.
The full DESI project, which is managed by Berkeley Lab, involves about 200 scientists and about 45 institutions from around the globe. DESI will provide the most detailed 3-D map of the universe and probe the secrets of dark energy, which is accelerating the universe's expansion. It is also expected to improve our understanding of dark matter, the infant universe, and the structure of our own galaxy.
The thin, cylindrical robots that will be tested in ProtoDESI each carry a fiber-optic cable that will be precisely pointed at selected objects in the night sky in order to capture their light. A predecessor galaxy-measuring project, called BOSS, required the light-gathering cables to be routinely plugged by hand into metal plates with holes drilled to match the position of pre-selected sky objects. DESI will automate and greatly speed up this process.
Each 10-inch-long robot has two small motors in it that allow two independent rotating motions to position a fiber anywhere within a circular area 12 millimeters in diameter. In the completed DESI array, these motions will enable the 5,000 robots to cover every point above their metal, elliptical base, which measures about 2.5 feet across.
That requires precise, software-controlled choreography so that the tightly packed robots don't literally bump heads as they spin into new positions several times each hour to collect light from different sets of pre-selected sky objects. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
DESI, the Dark Energy Spectroscopic Instrument, will measure light from 35M galaxies to provide new clues about dark energy.
A 3-D sky-mapping project that will measure the light of millions of galaxies has received formal approval from the U.S. Department of Energy to move forward with construction. Installation of the project, called DESI (Dark Energy Spectroscopic Instrument), is set to begin next year at the Nicholas U. Mayall 4-meter telescope at Kitt Peak National Observatory near Tucson, Ariz., with observations starting up in January 2019.
This latest DOE approval step, known as Critical Decision 3, triggers spending for major components of the project, including the remainder of the 5,000 finger-width, 10-inch-long cylindrical robots that will precisely point the fiber-optic cables to gather the light from a chosen set of galaxies, stars, and brilliant objects called quasars. The spending will also be used to complete the set of 10 fiber-fed spectrographs that will precisely measure different wavelengths of incoming light.
This light will tell us about the properties of the galaxies, stars, and quasars, and most importantly, how quickly they are moving away from us—light from objects that are moving away from us is shifted to redder wavelengths (“redshift”). These details can help us learn more about the nature of dark energy that is driving the accelerating expansion of the universe. DESI’s observations will provide a deep look back in time, up to about 11 billion years ago. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Researchers design mock galaxies and more to prepare for sky-mapping instrument
Seeing is believing, or so the saying goes.
And in some cases, a world of make-believe can help you realize what you’re actually seeing, too.
Scientists are creating simulated universes, for example – complete with dark matter mock-ups, computer-generated galaxies, quasi quasars, and pseudo supernovae – to better understand real-world observations.
Their aim is to envision how new Earth-based and space-based sky surveys will see the universe, and to help analyze and interpret the vast treasure troves of data that these surveys will amass. ...
Several DESI teams are building out separate simulations populated with the many types of objects DESI will encounter. ...
The computerized models are informed by observations from previous surveys and by large-scale simulations of the universe that account for complex physics including dark matter, an unknown form of matter that, together with dark energy, makes up about 95 percent of the total mass and energy in the universe. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
A new chapter opens today in the history of the 4-m Mayall telescope, the largest aperture telescope at NSF’s Kitt Peak National Observatory (KPNO). Having completed its first 45-year-long assignment, the telescope is now poised to embark on a new mission: creating the largest 3-dimensional map of the cosmos to date. The map will help astronomers chart out the role of dark energy in the expansion history of the Universe.
When the Mayall first opened its eye to the sky 45 years ago, it was one of the largest optical telescopes in existence. Designed to be versatile, its mission was to assist astronomers in addressing the wide diversity of astronomical questions facing the field. Tremendously successful, it played an important role in many astronomical discoveries, such as establishing the role of dark matter in the Universe from measurements of galaxy rotation, and determining the scale and structure of the Universe.
Today it sheds its identity as an “all-purpose research tool” and, reinventing itself, turns to a new dedicated mission that will tackle one of the most profound problems in physics: understanding the mysterious physics of dark energy, an unknown form of energy that is believed to permeate all of space and accelerate the expansion of the Universe.
To prepare for its new mission, the Mayall will close temporarily. Over the next 15 months, it will undergo the largest overhaul in its history in preparation for the installation of the Dark Energy Spectroscopic Instrument (DESI) , a massively parallel optical spectrometer capable of measuring the spectra of 5000 astronomical objects simultaneously. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Key components for the sky-mapping Dark Energy Spectroscopic Instrument (DESI), weighing about 12 tons, were hoisted atop the Mayall Telescope at Kitt Peak National Observatory (KPNO) near Tucson, Arizona, and bolted into place Wednesday, marking a major project milestone.
DESI will create the largest 3-D map of the universe by gathering light from tens of millions of galaxies after its scheduled startup in late 2019. It is designed to provide more precise measurements of dark energy, which is accelerating the universe’s expansion and looms as one of the universe’s biggest mysteries. ...
The new top-end components include a 3.4-ton barrel-shaped, steel-framed structure, known as a corrector, that houses a precisely stacked array of large (the largest is 1.1 meters in diameter), delicate lenses. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
On April 1, the dome of the Mayall Telescope near Tucson, Arizona, opened to the night sky, and starlight poured through the assembly of six large lenses that were carefully packaged and aligned for a new instrument that will launch later this year.
Just hours later, scientists produced the first focused images with these precision lenses – the largest is 1.1 meters in diameter – during this early test spin, marking an important “first light” milestone for the Dark Energy Spectroscopic Instrument, or DESI. This first batch of images homed in on the Whirlpool Galaxy to demonstrate the quality of the new lenses. ...
This phase of the project will continue for about six weeks and will require the efforts of several onsite scientists and remote observers ... When completed later this year, DESI will see and measure the sky’s light in a far different way than this assembly of lenses. It is designed to take in thousands of points of light instead of a single, large picture.
The finished DESI will measure the light of tens of millions of galaxies reaching back 12 billion light-years across the universe. It is expected to provide the most precise measurement of the expansion of the universe and provide new insight into dark energy, which scientists explain is causing this expansion to accelerate. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
<<In April 1964, Gene Roddenberry presented the Star Trek draft to DESIlu Productions, a leading independent television production company. He met with Herbert F. Solow, DESIlu's Director of Production. Solow saw promise in the idea and signed a three-year program-development contract with Roddenberry. Lucille Ball, head of DESIlu, was not familiar with the nature of the project, but she was instrumental in getting the pilot produced.
DESIlu Productions had a first look deal with CBS. Oscar Katz, DESIlu's Vice President of Production, went with Roddenberry to pitch the series to the network. They refused to purchase the show, as they already had a similar show in development, the 1965 Irwin Allen series Lost in Space.
In May 1964, Solow, who previously worked at NBC, met with Grant Tinker, then head of the network's West Coast programming department. Tinker commissioned the first pilot – which became "The Cage". NBC turned down the resulting pilot, stating that it was "too cerebral". However, the NBC executives were still impressed with the concept, and they understood that its perceived faults had been partly because of the script that they had selected themselves.
NBC made the unusual decision to pay for a second pilot, using the script called "Where No Man Has Gone Before". Only the character of Spock, played by Leonard Nimoy, was retained from the first pilot, and only two cast members, Majel Barrett and Nimoy, were carried forward into the series. This second pilot proved to be satisfactory to NBC, and the network selected Star Trek to be in its upcoming television schedule for the fall of 1966.
The second pilot introduced most of the other main characters: Captain Kirk (William Shatner), Chief Engineer Lt. Commander Scott (James Doohan) and Lt. Sulu (George Takei), who served as a physicist on the ship in the second pilot but subsequently became a helmsman throughout the rest of the series.
In February 1966, Star Trek was nearly canceled by DESIlu Productions, before airing the first episode. DESIlu had gone from making just one half-hour show (The Lucy Show), to deficit financing a portion of two expensive hour-long shows, Mission: Impossible and Star Trek. Solow was able to convince Lucille Ball that both shows should continue.>>
<<In April 1964, Gene Roddenberry presented the Star Trek draft to DESIlu Productions, a leading independent television production company. He met with Herbert F. Solow, DESIlu's Director of Production. Solow saw promise in the idea and signed a three-year program-development contract with Roddenberry. Lucille Ball, head of DESIlu, was not familiar with the nature of the project, but she was instrumental in getting the pilot produced.
DESIlu Productions had a first look deal with CBS. Oscar Katz, DESIlu's Vice President of Production, went with Roddenberry to pitch the series to the network. They refused to purchase the show, as they already had a similar show in development, the 1965 Irwin Allen series Lost in Space.
In May 1964, Solow, who previously worked at NBC, met with Grant Tinker, then head of the network's West Coast programming department. Tinker commissioned the first pilot – which became "The Cage". NBC turned down the resulting pilot, stating that it was "too cerebral". However, the NBC executives were still impressed with the concept, and they understood that its perceived faults had been partly because of the script that they had selected themselves.
NBC made the unusual decision to pay for a second pilot, using the script called "Where No Man Has Gone Before". Only the character of Spock, played by Leonard Nimoy, was retained from the first pilot, and only two cast members, Majel Barrett and Nimoy, were carried forward into the series. This second pilot proved to be satisfactory to NBC, and the network selected Star Trek to be in its upcoming television schedule for the fall of 1966.
The second pilot introduced most of the other main characters: Captain Kirk (William Shatner), Chief Engineer Lt. Commander Scott (James Doohan) and Lt. Sulu (George Takei), who served as a physicist on the ship in the second pilot but subsequently became a helmsman throughout the rest of the series.
In February 1966, Star Trek was nearly canceled by DESIlu Productions, before airing the first episode. DESIlu had gone from making just one half-hour show (The Lucy Show), to deficit financing a portion of two expensive hour-long shows, Mission: Impossible and Star Trek. Solow was able to convince Lucille Ball that both shows should continue.>>
Researchers will pick 35 million galaxies and quasars to target during DESI’s 5-year mission
A multicolor mosaic image of the massive galaxy cluster, Abell 370, located in the
constellation Cetus. Abell 370 formed when two less massive galaxy clusters merged
together billions of years ago. It is more than 6.5 billion light-years away from Earth.
The mosaic is approximately 4.5 million light-years across and has been constructed
from deep optical imaging in the Legacy Surveys’ eighth data release. (Credit: John Moustakas/Siena College; Legacy Surveys Team)
It took three sky surveys – conducted at telescopes in two continents, covering one-third of the visible sky, and requiring almost 1,000 observing nights – to prepare for a new project that will create the largest 3D map of the universe’s galaxies and glean new insights about the universe’s accelerating expansion.
This Dark Energy Spectroscopic Instrument (DESI) project will explore this expansion, driven by a mysterious property known as dark energy, in great detail. It could also make unexpected discoveries during its five-year mission.
The surveys, which wrapped up in March, have amassed images of more than 1 billion galaxies and are essential in selecting celestial objects to target with DESI, now under construction in Arizona.
The latest batch of imaging data from these surveys, known as DR8, was publicly released July 8, and an online Sky Viewer tool provides a virtual tour of this data. A final data release from the DESI imaging surveys is planned later this year.
Scientists will select about 33 million galaxies and 2.4 million quasars from the larger set of objects imaged in the three surveys. Quasars are the brightest objects in the universe and are believed to contain supermassive black holes. DESI will target these selected objects for several measurements after its start, which is expected in February 2020.
DESI will measure each target across a range of different wavelengths of light, known as spectrum, from the selected set of galaxies repeatedly over the course of its mission. These measurements will provide details about their distance and acceleration away from Earth.
A collection of 5,000 swiveling robots, each carrying a fiber-optic cable, will point at sets of pre-selected sky objects to gather their light (see a related video) so it can be split into different colors and analyzed using a series of devices called spectrographs. ...
The three imaging surveys for DESI include:
The Mayall z-band Legacy Survey (MzLS), carried out at the Mayall Telescope at the National Science Foundation’s Kitt Peak National Observatory near Tucson, Arizona, over 401 nights. DESI is now under installation at the Mayall Telescope.
The Dark Energy Camera Legacy Survey (DECaLS) at the Victor Blanco Telescope at NSF’s Cerro Tololo Inter-American Observatory in Chile, which lasted 204 nights.
The Beijing-Arizona Sky Survey (BASS), which used the Steward Observatory’s Bok telescope at Kitt Peak National Observatory and lasted 375 nights.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
With installation near completion, new sky-surveying instrument begins final testing
DESI by the Numbers (Credit: Marilyn Chung/Berkeley Lab)
A new instrument mounted atop a telescope in Arizona has aimed its robotic array of 5,000 fiber-optic “eyes” at the night sky to capture the first images showing its unique view of galaxy light.
It was the first test of the Dark Energy Spectroscopic Instrument, known as DESI, with its nearly complete complement of components. The long-awaited instrument is designed to explore the mystery of dark energy, which makes up about 68 percent of the universe and is speeding up its expansion.
DESI’s components are designed to automatically point at preselected sets of galaxies, gather their light, and then split that light into narrow bands of color to precisely map their distance from Earth and gauge how much the universe expanded as this light traveled to Earth. In ideal conditions DESI can cycle through a new set of 5,000 galaxies every 20 minutes.
The latest milestone, achieved Oct. 22, marks the opening of DESI’s final testing toward the formal start of observations in early 2020. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
This video contains animations showing how the complex components of the
Dark Energy Spectroscopic Instrument, installed on the Mayall Telescope at
Kitt Peak National Observatory near Tucson, Arizona, work together. (Credit: Dongjae “Krystofer” Kim/Kryated.com, DESI Collaboration)
The Dark Energy Spectroscopic Instrument, which will map millions of galaxies in 3D, reaches final milestone toward its startup
Even as the Dark Energy Spectroscopic Instrument, or DESI, lies dormant within a telescope dome on a mountaintop in Arizona, due to the COVID-19 pandemic, the DESI project has moved forward in reaching the final formal approval milestone prior to startup.
DESI is designed to gather the light of tens of millions of galaxies, and several million ultrabright deep-sky objects called quasars, using fiber-optic cables that are automatically positioned to point at 5,000 galaxies at a time by an orchestrated set of swiveling robots. The gathered light is measured by a group of 10 devices called spectrographs, which split the light into its spectrum, or separate colors.
The measurements will help scientists map the universe in 3D and learn more about mysterious dark energy – which drives the universe’s accelerating expansion – and could also provide new insight about the life cycle of galaxies and about the cosmic web that connects matter in the universe. ...
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
