The first released VST image shows the spectacular star-forming region Messier 17, also known as the Omega Nebula or the Swan Nebula. Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: OmegaCen/Astro-WISE/Kapteyn Institute.
[/caption]
There’s a new telescope at the Paranal Observatory in Chile and what big eyes it has! The VLT Survey Telescope (VST) is a wide-field survey telescope with a field of view twice as broad as the full Moon, enabling new, spectacular views of the cosmos. It is the largest telescope in the world designed to exclusively survey the sky in visible light. Over the next few years the VST and its camera OmegaCAM will make several very detailed surveys of the southern sky.
The first image released from these new eyes on the Universe is a spectacular view star-forming region Messier 17, also known as the Omega Nebula or the Swan Nebula, shown above. The VST field of view is so large that the entire nebula, including its fainter outer parts, is captured — and retains its superb sharpness across the entire image.
This new image may be the best portrait of the globular star cluster Omega Centauri ever made. Omega Centauri, in the constellation of Centaurus (The Centaur), is the largest globular cluster in the sky, but the very wide field of view of VST and its powerful camera OmegaCAM can encompass even the faint outer regions of this spectacular object. Credit: ESO/INAF-VST/OmegaCAM. Acknowledgement: A. Grado/INAF-Capodimonte Observatory
The second image is the globular star cluster Omega Centauri. This is the largest globular cluster in the sky, but the very wide field of view of VST and OmegaCAM allows even the faint outer regions to be seen clearly. This view includes about 300,000 stars.
Here’s a look at the new telescope:
The VLT Survey Telescope (VST) is the latest telescope to be added to ESO’s Paranal Observatory in the Atacama Desert of northern Chile. Credit: ESO/G. Lombardi
Below is a timelapse sequences of the VST enclosure at night:
NASA's Chandra X-ray Observatory reveals the complex X-ray-emitting central region of the Crab Nebula. This image is 9.8 light-years across. Chandra observations were not compatible with the study of the nebula's X-ray variations. Credit: NASA/CXC/SAO/F. Seward et al.
The famous Crab Nebula supernova remnant has erupted in an enormous flare five times more powerful than any flare previously seen from the object. On April 12, NASA’s Fermi Gamma-ray Space Telescope first detected the outburst, which lasted six days. Several other satellites also made observations, which has astonished astronomers by revealing unexpected changes in X-ray emission the Crab, once thought to be the steadiest high-energy source in the sky.
The nebula is the wreckage of an exploded star that emitted light which reached Earth in the year 1054. It is located 6,500 light-years away in the constellation Taurus. At the heart of an expanding gas cloud lies what is left of the original star’s core, a superdense neutron star that spins 30 times a second. With each rotation, the star swings intense beams of radiation toward Earth, creating the pulsed emission characteristic of spinning neutron stars (also known as pulsars).
Apart from these pulses, astrophysicists believed the Crab Nebula was a virtually constant source of high-energy radiation. But in January, scientists associated with several orbiting observatories, including NASA’s Fermi, Swift and Rossi X-ray Timing Explorer, reported long-term brightness changes at X-ray energies.
X-ray data from NASA's Fermi, RXTE, and Swift satellites and the European Space Agency's International Gamma-Ray Astrophysics Laboratory (INTEGRAL) confirm that the Crab Nebula's output has declined about 7 percent in two years at energies from 15,000 to 50,000 electron volts. They also show that the Crab has brightened or faded by as much as 3.5 percent a year since 1999. Fermi's Large Area Telescope (LAT) has detected powerful gamma-ray flares (magenta lines) as well. (Image credit: NASA's Goddard Space Flight Center)
“The Crab Nebula hosts high-energy variability that we’re only now fully appreciating,” said Rolf Buehler, a member of the Fermi Large Area Telescope (LAT) team at the Kavli Institute for Particle Astrophysics and Cosmology, a facility jointly located at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University.
Since 2009, Fermi and the Italian Space Agency’s AGILE satellite have detected several short-lived gamma-ray flares at energies greater than 100 million electron volts (eV) — hundreds of times higher than the nebula’s observed X-ray variations. For comparison, visible light has energies between 2 and 3 eV.
On April 12, Fermi’s LAT, and later AGILE, detected a flare that grew about 30 times more energetic than the nebula’s normal gamma-ray output and about five times more powerful than previous outbursts. On April 16, an even brighter flare erupted, but within a couple of days, the unusual activity completely faded out.
“These superflares are the most intense outbursts we’ve seen to date, and they are all extremely puzzling events,” said Alice Harding at NASA’s Goddard Space Flight Center in Greenbelt, Md. “We think they are caused by sudden rearrangements of the magnetic field not far from the neutron star, but exactly where that’s happening remains a mystery.”
The Crab’s high-energy emissions are thought to be the result of physical processes that tap into the neutron star’s rapid spin. Theorists generally agree the flares must arise within about one-third of a light-year from the neutron star, but efforts to locate them more precisely have proven unsuccessful so far.
Since September 2010, NASA’s Chandra X-ray Observatory routinely has monitored the nebula in an effort to identify X-ray emission associated with the outbursts. When Fermi scientists alerted astronomers to the onset of a new flare, Martin Weisskopf and Allyn Tennant at NASA’s Marshall Space Flight Center in Huntsville, Ala., triggered a set of pre-planned observations using Chandra.
It was also observed by NASA’s Rossi X-Ray Timing Explorer (RXTE) and Swift satellites and the European Space Agency’s International Gamma-Ray Astrophysics Laboratory (INTEGRAL). The results confirm a real intensity decline of about 7 percent at energies between 15,000 to 50,000 eV over two years. They also show that the Crab has brightened and faded by as much as 3.5 percent a year since 1999.
“Thanks to the Fermi alert, we were fortunate that our planned observations actually occurred when the flares were brightest in gamma rays,” Weisskopf said. “Despite Chandra’s excellent resolution, we detected no obvious changes in the X-ray structures in the nebula and surrounding the pulsar that could be clearly associated with the flare.”
Scientists think the flares occur as the intense magnetic field near the pulsar undergoes sudden restructuring. Such changes can accelerate particles like electrons to velocities near the speed of light. As these high-speed electrons interact with the magnetic field, they emit gamma rays.
To account for the observed emission, scientists say the electrons must have energies 100 times greater than can be achieved in any particle accelerator on Earth. This makes them the highest-energy electrons known to be associated with any galactic source. Based on the rise and fall of gamma rays during the April outbursts, scientists estimate that the size of the emitting region must be comparable in size to the solar system.
A portion of the Lagoon nebula imaged by the Gemini South telescope with the Gemini Multi-Object Spectrograph. Credit: Julia I. Arias and Rodolfo H. Barbá Departamento de Física, Universidad de La Serena (Chile), and ICATE-CONICET (Argentina).
[/caption]
Wow, is this gorgeous or what?! Argentinean astronomers Julia Arias and Rodolfo Barbá used the Gemini South telescope in Chile to obtain this stunning new image, allowing us to dive right into part of the Lagoon Nebula (M8). This region of the Lagoon is sometimes called the “Southern Cliff” because it resembles a sharp drop-off. Beyond the cliff, light from a spattering of young background stars in the upper left of the image shines through the cloudscape.
The Lagoon nebula is located near the constellation Sagittarius in the southern Milky Way. Viewed through large amateur telescopes, it appears as a pale ghostly glow with a touch of pink. In this image, the astronomers used special filters to reveal characteristics of the gas clouds. The reds, blues and greens represent each of three data sets results in a very strong color differentiation. And so, this isn’t what the Lagoon Nebula would actually look like were we to travel there and take a look with our own eyes. Two narrow-band optical filters sensitive to hydrogen (red) and ionized sulfur (green) emission, and another that transmits far red light (blue). And so, for example, light from the far-red end of the spectrum, beyond what the eye can see, appears blue in this image.
Arias and Barbá obtained the imaging data to explore the evolutionary relationship between the newborn stars and what are known as Herbig-Haro (HH) objects. HH objects form when young stars eject large amounts of fast-moving gas as they grow. This gas plows into the surrounding nebula, producing bright shock fronts that glow as the gas is heated by friction and surrounding gas is excited by the high-energy radiation of nearby hot stars. The researchers found a dozen of these HH objects in the image, spanning sizes that range from a few thousand astronomical units (about a trillion kilometers) to 1.4 parsecs (4.6 light-years), i.e. a little greater than the distance from the Sun to its nearest neighbor Proxima Centauri.
Andromeda is a beautiful galaxy to see with your own eyes, but in this video, ESA’s fleet of space telescopes — XMM Newton, Herschel, Planck and several ground-based telescopes — has captured M31, in different wavelengths, most of which are invisible to the eye. Each wavelength shows a different aspect of the galaxy’s nature, as well as providing a look at the lifecycle of the stars that make up Andromeda. Continue reading “The Many Colors and Wavelengths of the Andromeda Galaxy”
Image of NGC 6872 (left) and companion galaxy IC 4970 (right) locked in a tango as the two galaxies gravitationally interact. The galaxies lie about 200 million light-years away in the direction of the constellation Pavo (the Peacock). Image credit: Sydney Girls High School Astronomy Club, Travis Rector (University of Alaska, Anchorage), Ángel López-Sánchez (Australian Astronomical Observatory/Macquarie University), and the Australian Gemini Office.
[/caption]
More than just another pretty picture? I’ll say! This beautiful image of the galaxy pair NGC 6872 and IC 4970 was part of a competition for high school students in Australia to obtain scientifically useful (and aesthetically pleasing) images using the Gemini Observatory. The winners were students from the Sydney Girls High School Astronomy Club in central Sydney, who proposed that Gemini investigate these two galaxies that are embraced in a graceful galactic dance that, — as the team described in the essay to support their entry — “…will also serve to illustrate the situation faced by the Milky Way and the Andromeda galaxy in millions of years.”
We can only hope we look this pretty millions of years from now!
This image shows what happens when galaxies interact, and how the gravitational forces distort and tear away at their original structure. Spiral galaxies can have their arms elongate out to enormous distances: in NGC 6872, the arms have been stretched out to span hundreds of thousands of light-years—many times further than the spiral arms of our own Milky Way galaxy. Over hundreds of millions of years, NGC 6872’s arms will fall back toward the central part of the galaxy, and the companion galaxy (IC 4970) will eventually be merged into NGC 6872.
But that will be another pretty picture, as galaxy mergers often leads to a burst of new star formation. Already, the blue light of recently created star clusters dot the outer reaches of NGC 6872’s elongated arms. Dark fingers of dust and gas along the arms soak up the visible light. That dust and gas is the raw material out of which future generations of stars could be born.
Members of the SGHS Astronomy Club Executive Council receiving the Gemini image on behalf of the entire club. Photo credit: Australian Gemini Office.
View from a helicopter of the summit of Mauna Kea in Hawaii. Image: Nancy Atkinson
[/caption]
For about 300 nights out of the year, Mauna Kea on the Big Island of Hawaii is one of the best places in the world for ground-based astronomy. At an elevation of 4,205 meters (13,796 ft), the summit sits above a large portion of the Earth’s atmosphere, and usually, the sky is clear, calm and dry. Indeed, 13 giant telescopes sit Mauna Kea’s summit, and they have made some of the biggest discoveries in astronomy. But for the remaining nights of the year, a variety of weather-related issues can keep astronomers from observing, and visitors from climbing to the summit to see those pristine skies for themselves, as well as being able to watch some of our biggest eyes on the skies action. Sometimes clouds, high winds or humidity might keep the telescope domes closed, other times snow can close the roads. On a recent visit to Hawaii, heavy snow kept the roads closed for three days and my long-planned trip to the top of Mauna Kea was, disappointingly, scrubbed. But I did get a great behind the scenes tour of the W. M. Keck Observatory headquarters in Waimea.
The Keck Headquarters and visitor center in Waimea.
While the telescopes are up at at the top of the mountain, astronomers seldom actually work at the telescopes themselves. Instead they work out of remote operations offices at the headquarters in Waimea. There is an operations room for each of the twin 10-meter Keck telescopes: Remote Operations 1 works the Keck 1 telescope:
Remote Operations Room 1 for Keck 1. Image: Nancy Atkinson
And Remote Operations 2 works Keck 2:
Remote Operations Room 2 at the Keck Headquarters. Image: Nancy Atkinson
I arrived in the morning before any of the astronomers were there. “People who work for Keck help the visiting astronomers,” said Alexandra Starr, who works with the media and is a public information officer at the Keck headquarters. “Usually, the visiting astronomers start filtering in about 2 o’clock, and the people who work on the summit get things ready for what the astronomers want to observe. There is a camera for those down here to view how things are going for getting the telescope pointed exactly where they want it.”
But the domes on the telescope can’t be opened until the sun goes down.
“So, once they get everything set up, they go for an early dinner and then come back here and observe all night long,” said Starr. “We do have people working around the clock, however. For astronomers who have been here before, sometimes they don’t need a lot of assistance, but our support astronomers will help all the visiting astronomers get the best observing they can, and get the information they need while they are on the sky.”
About 125 people work full-time at Keck, of which two-thirds are local people from from Hawaii. With an annual operating budget of $11 million, the Observatory is one of the town’s largest employers.
At the headquarters, there are condos where the visiting astronomers can stay:
Facilities where visiting astronomers stay while at Keck. Image: Nancy Atkinson
Most astronomers have just two nights for observing, and Starr said it can be up to a year and a half from when astronomers submit a proposal to use the Keck telescopes to when they actually get to observe. But sometimes, depending on the astronomer and what they are observing, they’ll get to return again fairly quickly when the weather doesn’t allow for observing.
“The past 2 nights we haven’t been observing, and those people are in town ready to go,” Starr said.
The backside of facilities includes the observatory’s own mechanics shop. “We have eight 4-wheel drive automobiles to get to the summit, and our own mechanic shop to keep them all in top shape,” Starr said.
The Keck Observatory’s headquarters in Waimea is open to visitors, and volunteer guides are available Tuesday through Friday from 10 a.m. to 2 p.m. to share information about Keck and the other Mauna Kea observatories. The visitor’s center also has a conference room for public lectures from visiting astronomers.
Inside are models and images of the twin 10-meter Keck telescopes:
Models of the twin Keck telescopes inside the Keck visitor center. Image: Nancy Atkinson
The twin Keck telescopes are the world’s largest optical and infrared telescopes. Each telescope stands eight stories tall, weighs 300 tons and operates with nanometer precision. The telescopes’ primary mirrors are 10 meters in diameter and are each composed of 36 hexagonal segments that work in concert as a single piece of reflective glass.
Outside in the visitor center courtyard is a grassy area that represents the size of just one of the hexagonal segments, which are 1.8 meters (6 ft) in diameter.
The grassy area in the courtyard of the Keck Observatory visitor center is the same size as one of the 36 hexagonal glass segments that make up the 10-meter mirrors on the two Keck telescopes. Image: Nancy Atkinson
Each segment weighs .5 metric tons (880 pounds), and are three inches thick. They are made of a glass and ceramic composite called Zerodur. Zerodur itself is not reflective, so they are covered with a thin reflective layer of aluminum.
“While the telescope is actually working it is constantly fine tuning the position of the individual mirrors to make sure they are all in alignment,” said our tour guide Rosalind Redfield.
On the telescope, each segment’s figure is kept stable by a system of extremely rigid support structures and adjustable warping harnesses. During observing, a computer-controlled system of sensors and actuators adjusts the position of each segment – relative to the neighboring segment – to an accuracy of four nanometers, about the size of a few molecules, or about 1/25,000 the diameter of a human hair. This twice-per-second adjustment effectively counters the tug of gravity.
The twin Kecks, Subaru and IRTF seen from the eastern ridge at sunset. Credit: Pablo McLoud/Keck
Up at the summit, (which I can only share pictures provided by the Keck Observatory) Redfield said it is like the other side of the Moon. “Absolutely nothing grows up there, the elevation is so high it is completely barren,” she said. “There is fine, sandy type dirt, and they don’t like people driving up there as it stirs up dust. The paved road only goes so far, and anyone driving at the summit creates enough dust that it can cause a problem, and people are only allowed to drive up if you have a four-wheel drive.”
The sun sets on Mauna Kea as the twin Kecks prepare for observing. Credit: Laurie Hatch/ W. M. Keck Observatory
Mauna Kea summit as seen from the northeast. Credit: University of Hawaii.
The two Keck telescopes and the 8.3 meter Subaru telescopes take the very top of the mountain. They are joined by the 8.1 Gemini North Telescope , the 0.6-m educational telescope, from the University of Hawaii at Hilo, a 2.2-m telescope University of Hawaii Institute for Astronomy, the 3 meter NASA Infrared Telescope Facility, the 3.6 meter Canada-France-Hawaii Telescope, the 3.8 meter UKIRT (United Kingdom Infrared Telescope), the 10.4 Caltech Submillimeter Observatory, the 15 meter James Clerk Maxwell Telescope, the 8X6 meter Submillimeter Array and the 25 meter Very Long Baseline Array.
A map of the telescopes on Mauna Kea. Credit: University of Hawaii.
But, no climb to the summit for me — not this time anyway! I hope to return one day to Mauna Kea to see first-hand where science and nature come together to allow for continued discovery of our universe.
Clouds and snow obscure the summit of Mauna Kea as I drive away, after a climb to visit the Keck telescopes was nixed. Image: Nancy Atkinson.
For more information about the Keck Observatory, see their website, and if you are in Hawaii or going to be visiting the Big Island, find information here on how you can visit the Observatory headquarters, or go to the summit.
The James Webb Space Telescope will have a sunshield that is about the size of a tennis court, and mission managers say it will offer the best “SPF” (Sun Protection Factor) in the Universe.
“Each of the five layers of the shield is less than half the thickness of a piece of paper,” said John Durning, Deputy Project Manager for JWST. “The five work together to create an effective SPF of 1,000,000.”
This sunshield protects the observatory from unwanted light, keeping it cool and allowing it to detect heat from faraway objects in the universe. So, how do you get something that large into orbit? Continue reading “JWST Sunscreen Offers SPF 1,000,000”
Richard Wainscoat (left) and Marco Micheli study one of the near-Earth asteroids found on January 29. The asteroid is the roundish dot near Wainscoat’s finger. Photo by Karen Teramura
The Pan-STARRS PS1 telescope on Haleakala, Maui, discovered 19 near-Earth asteroids on the night of January 29, the most asteroids discovered by one telescope on a single night.
“This record number of discoveries shows that PS1 is the world’s most powerful telescope for this kind of study,” said Nick Kaiser, head of the Pan-STARRS project. “NASA and the U.S. Air Force Research Laboratory’s support of this project illustrates how seriously they are taking the threat from near-Earth asteroids.”
Pan-STARRS software engineer Larry Denneau spent that Saturday night in his University of Hawaii at Manoa office in Honolulu processing the PS1 data as it was transmitted from the telescope over the Internet. During the night and into the next afternoon, he and others came up with 30 possible new near-Earth asteroids.
Asteroids are discovered because they appear to move against the background of stars. To confirm asteroid discoveries, scientists must carefully re-observe them several times within 12-72 hours to define their orbits, otherwise they are likely to be “lost.”
Denneau and colleagues quickly sent their discoveries to the Minor Planet Center in Cambridge, Mass., which collects and disseminates data about asteroids and comets, so that other astronomers can re-observe the objects.
“Usually there are several mainland observatories that would help us confirm our discoveries, but widespread snowstorms there closed down many of them, so we had to scramble to confirm many of the discoveries ourselves,” noted Institute for Astronomy astronomer Richard Wainscoat.
Wainscoat, astronomer David Tholen, and graduate student Marco Micheli spent the next three nights searching for the asteroids using telescopes at Mauna Kea Observatories, Hawaii.
On Sunday night, they confirmed that two of the asteroids were near-Earth asteroids before snow on Mauna Kea forced the telescopes to close. On Monday night, they confirmed nine more before fog set in.
On Tuesday night, they searched for four, but found only one. After Tuesday, the remaining unconfirmed near-Earth asteroids had moved too far to be found again.
Telescopes in Arizona, Illinois, Italy, Japan, Kansas, New Mexico, and the United Kingdom, and the Faulkes Telescope on Haleakala also helped to confirm seven of the discoveries.
Two of the asteroids, it turns out, have orbits that come extremely close to Earth’s. There is no immediate danger, but a collision in the next century or so, while unlikely, cannot yet be ruled out. Astronomers will be paying close attention to these objects.
Astronomer Scott Kardel on top of the 200-inch Hale Telescope at the Palomar Observatory shoveling snow. Image courtesy Scott Kardel.
Ah, the glamorous life of an astronomer. Scott Kardel, public affairs coordinator for the Palomar Observatory, found himself on top of the dome of the 200-inch Hale Telescope — not observing, but shoveling. Snow. Palomar Mountain has been getting its share of the white stuff this winter, and this weekend close to a foot of snow fell in the area. All that snow can cause problems for using the telescope.
“The basic problem is this,” Kardel wrote on his blog, Palomar Skies. “If you open the dome with snow on the top, snow will fall in on the telescope and instrumentation. So a small crew, each secured with a safety harness, is sent up to remove the snow from the dome slit.”
Kardel posted a nice collection of scenic images from his foray on top of the snow-covered dome, adding that, “At Palomar Observatory every day is an adventure.”
The ESO's La Silla telescope site in the southern Atacama Desert, Chile. Credit: Iztok Boncina/ESO
[/caption]
It’s difficult enough to imagine stark white telescope domes towering over a parched brown landscape made even more arid by the near-constant whistle of high-altitude winds. It’s stranger still to consider that in the desert below those domes, tough and grieving women have been searching in vain for decades for the sun-bleached remains of loved ones stolen from them, killed and dumped in the void by Pinochet’s army.
Acclaimed Chilean film director Patricio Guzmán has woven these stories together into a documentary called Nostalgia de la Luz, or Nostalgia for the Light, that is both touching and stunning, human and other-worldly, emotional — and hopeful.
In fact Jason Glenn, an astronomer at the University of Colorado at Boulder, took the podium for a few moments before the start of the film to announce plans for the Cornell-Caltech-Atacama (CCAT) telescope proposed to go atop the Chilean mountain Cerro Chajnantor — and to request donations toward its construction. CCAT, a submillimeter telescope, will be used to probe primeval galaxies, star formation and extra-solar planetary systems.
The film opens with awe-inspiring images of galaxies, close-up views of the pockmarked lunar surface, and eerily beautiful shots of the vast Atacama. The desert lies west of the Andes Mountains in Chile, and is generally regarded as the driest place on Earth. That, plus its high altitude, make it a perfect place for astronomy. The Atacama supports the ESO’s Atacama Large Millimeter/submillimeter Array (ALMA), the Very Large Telescope (VLT) and numerous other instruments. Many Chileans, the film intimates, grow up loving astronomy.
Meanwhile the people of Chile continue to heal from Pinochet’s bloody rule beginning in the early 1970s, when thousands of his political opponents were taken from their families and disappeared. The film captures the perspectives of people on all sides of the tragedy — from the grieving mothers and wives, the archeologists working to decipher both the recent and distant human past, survivors of Pinochet’s concentration camps and even astronomers who, tucked in offices underneath the massive telescope domes, might not seem to have much in common with the grieving women. But they do.
Gaspar Galaz, an astronomer at the Pontifical Catholic University of Chile, says in the film that both he and the women pursue quests to learn history; they’re all chasing rare clues in dauntingly vast spaces. Galaz peers far across the cosmos to study diffuse galaxies, whose origins are unknown, and the women comb the 40,600 square mile (105,000 km2) desert for minute fragments of bone. The difference: At the end of his workday, Galaz says, he can get a good night’s sleep, “but these women must have trouble sleeping after they search for human remains.”
Nostalgia de la Luz is worth seeing for any of its parts — the glimpses through the powerful Atacama telescopes, the desert scenes, the cultural insights or the beautifully human and optimistic ending, which I won’t give away here. Taken together, the film’s elements are an experience not to be missed.
Several trailers for Nostalgia de la Luz are available on YouTube; upcoming showtimes include, according to Facebook, March 8 and 9 at the Wexner Center for the Arts in Columbus, Ohio, March 18 at the IFC Film Center in New York and April 22-28 at Landmark’s Nuart Theater in LA. Today’s showing was at the Boulder International Film Festival.
