[meteorite-list] Next Generation of Adaptive Optics Arrive at the Large Binocular Telescope

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 16 Jun 2010 13:36:27 -0700 (PDT)
Message-ID: <201006162036.o5GKaRn7019006_at_zagami.jpl.nasa.gov>

http://intelligencer.ccit.arizona.edu/node/32405

FOR IMMEDIATE RELEASE
FROM THE UNIVERSITY OF ARIZONA

June 16, 2010

Contact information follows this story.

The Universe, Crisp and Clear

The next generation of adaptive optics has arrived at the Large
Binocular Telescope in Arizona, providing astronomers with a new level
of image sharpness surpassing that of the Hubble Space Telescope.

The next generation of adaptive optics has arrived at the Large
Binocular Telescope in Arizona, providing astronomers with a new level
of image sharpness never before seen.

Developed in a collaboration between Italy's Arcetri Observatory of
the Istituto Nazionale di Astrofisica, or INAF, and the University of
Arizona's Steward Observatory, this technology represents a remarkable
step forward for astronomy.

"This is an incredibly exciting time as this new adaptive optics
system allows us to achieve our potential as the world's most powerful
optical telescope," said Richard Green, director of the LBT. "The
successful results show that the next generation of astronomy has
arrived, while providing a glimpse of the awesome potential the LBT
will be capable of for years to come."

Until relatively recently, ground-based telescopes had to live with
wavefront distortion caused by the Earth's atmosphere that
significantly blurred the images of distant objects (this is why stars
appear to twinkle to the human eye). While there have been
advancements in adaptive optics technology to correct atmospheric
blurring, the LBT's innovative system takes this concept to a new level.

This success was achieved through the combination of several
innovative technologies. The first is the secondary mirror, which was
designed from the start to be a main component of the LBT rather than
an additional element as on other telescopes. The concave secondary
mirror is .91 meters in diameter (3 feet) and only 1.6 millimeters
thick.

The mirror is so thin and pliable that it can easily be manipulated by
actuators pushing on 672 tiny magnets glued to the back of the mirror,
which offers far greater flexibility and accuracy than previous
systems on other telescopes. An innovative "pyramid" sensor detects
atmospheric distortions and manipulates the mirror in real time to
cancel out the blurring, allowing the telescope to literally see as
clear as if there were no atmosphere.

Incredibly, the mirror is capable of making adjustments every one
thousandth of a second, with accuracy to better than 10 nanometers (a
nanometer is one millionth the size of a millimeter).

In closed-dome tests beginning May 12 and sky tests every night since
May 25, astronomer Simone Esposito and his INAF team tested the new
device, achieving exceptional results.

The LBT's adaptive optics system, called the First Light Adaptive
Optics system, or FLAO, immediately outperformed all other comparable
systems, delivering an image quality greater than three times sharper
than the Hubble Space Telescope using just one of the LBT's two 8.4
meter mirrors. When the adaptive optics are in place for both mirrors
and their light is combined appropriately, it is expected that the LBT
will achieve image sharpness 10 times that of the Hubble.

The index of the perfection of image quality is known as the Strehl
Ratio, with a ratio of 100 percent equivalent to an absolutely perfect
image. Without adaptive optics, the ratio for ground-based telescopes
is less than 1 percent. The adaptive optics systems on other major
telescopes today improve image quality up to about 30 percent to 50
percent in the near-infrared wavelengths where the testing was
conducted.

In the initial testing phase, the LBT's adaptive optics system has
been able to achieve unprecedented Strehl Ratio of 60 to 80 percent, a
nearly two-thirds improvement in image sharpness over other existing
systems.

The results exceeded all expectations and were so precise the testing
team had difficulty believing its findings. However, testing has
continued since the system was first put on the sky on May 25, and the
LBT's adaptive optics have functioned flawlessly and achieved peak
Strehl Ratios of 82 to 84 percent.

"The results on the first night were so extraordinary that we thought
it might be a fluke, but every night since the adaptive optics have
continued to exceed all expectations. These results were achieved
using only one of LBT's mirrors. Imagine the potential when we have
adaptive optics on both of LBT's giant eyes," Esposito said.

More images from the adaptive optics system are available at the LBT
Observatory website.

Development of the LBT's adaptive optics system took longer than a
decade through an international collaboration. INAF, in particular the
Arcetri Observatory, conceived the instrument design and developed the
electro-mechanical system, while the University of Arizona Mirror Lab
created the optical elements, and the Italian companies Microgate and
ADS International engineered several components.

A prototype system was previously installed on the Multiple Mirror
Telescope, or MMT, at Mt. Hopkins, Ariz. The MMT system uses roughly
half the number of actuators as the LBT's final version, but it
demonstrated the viability of the design. The LBT's infrared test
camera, which produced the accompanying images, was a joint
development of INAF in Bologna and the MPIA in Heidelberg.

"This has been a tremendous success for INAF and all of the partners
in the LBT," said Piero Salinari, research director at the Arcetri
Observatory, INAF. "After more than a decade and with so much care and
effort having gone into this project, it is really rewarding to see it
succeed so astoundingly."

The $120 million LBT on Mount Graham utilizes two giant 8.4 meter
mirrors and with the new adaptive optics the telescope will have the
resolution of a 22.8-meter, or approximately 75-foot telescope. The
new adaptive optics will enable versatile instruments such as the near-
infrared camera spectrometer, which allows astronomers to penetrate
interstellar dust clouds and reveal the secrets of the youngest and
most distant galaxies, to achieve their full potential on the LBT.

The LBT is an international collaboration among institutions in the
U.S., Italy and Germany. The LBT Corporation partners are:

The University of Arizona on behalf of the Arizona university system
Istituto Nazionale di Astrofisica, Italy
LBT Beteiligungsgesellschaft, Germany, representing the Max Planck
Society, the Astrophysical Institute Potsdam, and Heidelberg University
The Ohio State University
The Research Corporation, on behalf of The University of Notre Dame,
University of Minnesota and University of Virginia
###

CONTACTS:

Richard Green, Large Binocular Telescope Observatory (520-626-7088; rgreen at as.arizona.edu
)

Jennifer Fitzenberger, University Communications (520-621-9017; jfitzen at email.arizona.edu
)
  
Received on Wed 16 Jun 2010 04:36:27 PM PDT