Subaru 8-meter Telescope Damaged by Leaking Coolant

Orange-colored coolant covers the mirror surface of the Subaru Telescope. Credit: National Astronomical Observatory of Japan

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A “serious hardware incident” has shut down the Subaru Telescope indefinitely. A leak allowed orange-colored coolant to spill over the primary mirror and into the main camera, as well as into other instruments and the structure of the telescope. The damage is still being assessed. During the clean-up and recovery of equipment, nighttime observations have been suspended, as well as daytime summit tours of the telescope.

An announcement posted on the Subaru telescope website said that operators detected an error signal while shutting down the observation system at the end of the night shift during the early morning of Saturday, July 2, 2011.

When engineers arrived to assess the situation, they found extensive leakage of coolant (ethylene glycol) over most of the entire telescope. The leak originated from the “top unit” of the telescope, which is located at the center of the top ring and includes the Subaru Prime Focus Camera (Suprime-Cam) and auxiliary optics.

Although they promptly shut off the supply of coolant, a significant amount of leakage had already occurred, from the top unit itself down to the tertiary mirror, the primary mirror and some of its actuators, the Faint Object Camera and Spectrograph (FOCAS, a Cassegrain instrument) and its auxiliary optics, and the telescope floor.

The engineers attempted to clean up and remove as much coolant as possible. However, such areas as optics, control circuits, and the inside of Suprime-Cam and FOCAS were inaccessible during the initial clean-up.
The coolant consists of a mixture of water and ethylene glycol, a liquid commonly used in a vehicle’s radiator for cooling. The coolant is not corrosive and does not damage the primary mirror, which has a foundation of glass.

The Subaru Telescope is located on the Mauna Kea on the Big Island of Hawaii, with offices in the town of Hilo. The Subaru website said they will post updates on the status of the telescope and its recovery.

Source: Subaru Telescope website

Subaru Telescope Takes Montage of Hayabusa’s Return to Earth

The composite image from 11 images, each with 5 sec exposure, spaced by 35-50 sec. The magnitude of Hayabusa is estimated to be 21 mag. Credit: Subaru Telescope Team

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The world watched and waited for the Hayabusa spacecraft to make its return to Earth on June 13, 2010 and the people of Japan — who built and launched the little spacecraft that could (and did!) — were especially hopeful in watching and waiting. Japan’s Subaru Telescope (although located on Mauna Kea in Hawaii) turned its expectant eyes towards Hayabusa and captured the spacecraft’s flight between the Moon and Earth in 11 different images.

A note from the Subaru Telescope team:

During the busy time preparing the observations, Doctor Masafumi Yagi and his team managed to maneuver the telescope just in time to catch Hayabusa before it disappeared down south in the twilight sky. At that time, Hayabusa was a little less than half way between Moon and Earth. Five seconds exposures, each spaced by 35 – 50 seconds in the V filter with Suprime Cam, it showed up in clear trace at the position expected to be. Brightness is estimated to be only 21 magnitudes. At this level, one can see a background galaxy clearly.

We are waiting to hear more from the project team at ISAS/JAXA. In the meantime, congratulations to all who are involved in this unprecedented endeavor.

A GIF animation of the 11 images is available here — but be warned, the file is huge. You can click on the top image for a full-sized huge-ified image, too.

And here are some images of the recovery teams who picked up the sample return canister in the Woomera Prohibited Area in Australia. The canister will be taken to Japan and opened in a few weeks, or perhaps months, after rigorous testing. Only then will we find out if any asteroid samples made it in the canister for the ride back to Earth.

Recovery team makes sure all is safe with the sample return canister. Credit: JAXA
The recovery team handles the heat sheild for the Hayabusa sample return capsule. Credit: JAXA, Hayabusa Twitter feed.
JAXA's Hayabusa space capsule is transported inside a box to a clean room inside the Instrumentation Building at the Woomera Test Range, South Australia. Credit: Australian Science Media Centre

You can see more images of the canister retrieval at the Hayabusa Twitpic page and the Australian Science Media Centre’s Flickr page

Source: Subaru

Team Finds Most-Distant Galaxy Cluster Ever Seen

SXDF-XCLJ0218-0510. Max-Planck-Institut für extraterrestrische Physik

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Like a location from Star Wars, this galaxy cluster is far, far away and with origins a long, long time ago. With the ungainly name of SXDF-XCLJ0218-0510, this cluster is actually the most distant cluster of galaxies ever seen. It is a whopping 9.6 billion light years away, and X-ray and infrared observations show that the cluster hosts predominantly old, massive galaxies. This means the galaxies formed when the universe was still very young, so finding this cluster and being able to see it is providing new information not only about early galaxy evolution but also about history of the universe as a whole.

An international team of astronomers from the Max Planck Institute for Extraterrestrial Physics, the University of Tokyo and the Kyoto University discovered this cluster using the Subaru telescope along with the XMM-Newton space observatory to look in different wavelengths.

Using the Multi-Object Infrared Camera and Spectrometer (MOIRCS) on the Subaru telescope, the team was able to look in near-infrared wavelengths, where the galaxies are most luminous.

“The MOIRCS instrument has an extremely powerful capability of measuring distances to galaxies. This is what made our challenging observation possible,” said Masayuki Tanaka from the University of Tokyo. “Although we confirmed only several massive galaxies at that distance, there is convincing evidence that the cluster is a real, gravitationally bound cluster.”

Like a contour map, the arrows in the image above indicate galaxies that are likely located at the same distance, clustered around the center of the image. The contours indicate the X-ray emission of the cluster. Galaxies with confirmed distance measurements of 9.6 billion light years are circled. The combination of the X-ray detection and the collection of massive galaxies unequivocally proves a real, gravitationally bound cluster.

That the individual galaxies are indeed held together by gravity is confirmed by observations in a very different wavelength regime: The matter between the galaxies in clusters is heated to extreme temperatures and emits light at much shorter wavelengths than visible to the human eye. The team therefore used the XMM-Newton space observatory to look for this radiation in X-rays.

“Despite the difficulties in collecting X-ray photons with a small effective telescope size similar to the size of a backyard telescope, we detected a clear signature of hot gas in the cluster,” said Alexis Finoguenov from the Max Planck Institute for Extraterrestrial Physics.

The combination of these different observations in what are invisible wavelengths to the human eye led to the pioneering discovery of the galaxy cluster at a distance of 9.6 billion light years – some 400 million light years further into the past than the previously most distant cluster known.

An analysis of the data collected about the individual galaxies shows that the cluster contains already an abundance of evolved, massive galaxies that formed some two billion years earlier. As the dynamical processes for galaxy aging are slow, presence of these galaxies requires the cluster assembly through merger of massive galaxy groups, each nourishing its dominant galaxy. The cluster is therefore an ideal laboratory for studying the evolution of galaxies, when the universe was only about a third of its present age.

As distant galaxy clusters are also important tracers of the large scale structure and primordial density fluctuations in the universe, similar observations in the future will lead to important information for cosmologists. The results obtained so far demonstrate that current near infrared facilities are capable of providing a detailed analysis of distant galaxy populations and that the combination with X-ray data is a powerful new tool. The team therefore is continuing the search for more distant clusters.

Source: Max Planck Institute for Extraterrestrial Physics