FOR RELEASE: June 2, 2003
Gemini Observatory, Hilo, Hawai`i
Phone: 808/974-2510, Cell: 808/937-0845
Gemini Observatory, Hilo, Hawai`i
Phone: 808/974-2607 Cell: 808/960-2697
New Gemini Images Exemplify the Power of Adaptive Optics
This composite image shows a small section of the core of the globular cluster M-13 as imaged by the Altair adaptive optics system on Gemini North (upper blue inset; 0.060 arcsecond resolution). Beneath the Altair image is an uncorrected "natural seeing" image (0.26 arcsecond resolution). Wide-field background image courtesy of the Canada-France-Hawai`i Telescope/Coelum/Jean-Charles Cuillandre.
More images are available at: http://www.gemini.edu/media/images_2003-2.html
image was released today revealing new details at the heart of a famous star
cluster. The thousands of swarming stars at the cluster's core were made
visible by an innovative adaptive optics system called Altair that is currently
being commissioned on the Frederick C. Gillett Gemini Telescope on Mauna
of the first images from Altair (Altitude Conjugate Adaptive Optics for Infrared),
the high-resolution data reveal multitudes of stars with stunning clarity.
The dense star cluster known to generations of skywatchers as the Great Hercules
Cluster or M-13 is home to hundreds of thousands of stars that, in the center,
are often blurred by our atmosphere into a great glowing mass. "The resolution
obtained in these images is approximately equivalent to seeing the separation
between an automobile's headlights on the Golden Gate Bridge in San Francisco
while standing 3,850 kilometers away in Hawai`i," said Observatory Adaptive
Optics Scientist Dr. Francois Rigaut.
images of M-13, with and without Altair, as well as a spectacular reference
image of the entire cluster, provided by the Canada-France-Hawaii Telescope,
can be viewed and downloaded at: http://www.gemini.edu/media/images_2003-2.html.
detail in the Gemini images was made possible by Altair's unique ability
to correct starlight that has been blurred by atmospheric turbulence using
adaptive optics with altitude conjugation.
optics systems that are currently in use correct for distortions to starlight
by assuming that all of the distortions occur where starlight is collected
- near the surface of the telescope's primary mirror. In an altitude-conjugated
system like Gemini's, the distortions are assumed to be at the dominant turbulence
layer of the atmosphere. By conjugating or tuning the system for a specific
layer above the telescope, Altair can generate a more accurate model of the
starlight's path through our atmosphere.
with altitude conjugation is a pioneering new technique that is a powerful
way to measure and fix distortions to starlight, which traveled undisturbed
for vast distances through space until hitting pockets of warm and cold air
in earth's atmosphere," said Glen Herriot, the systems engineer who managed
the building of Altair in Victoria, BC at the laboratories of the National
Research Council of Canada. Altair is able to precisely correct the distorted
starlight up to 1,000 times per second using a sophisticated, deformable
mirror about the size of the palm of your hand. "The end result is," says
Herriot, "images that rival or even exceed the sharpness of pictures taken
Gemini Observatory personnel, the Canadian team headed by Project Manager
Herriot and Project Scientist Dr. Jean-Pierre Véran, have been commissioning
Altair on Gemini North from late 2002 through early 2003. The instrument
team, comprised of 25 scientists and engineers, guided the Gemini adaptive
optics system from design to commissioning over the past six years. "Commissioning
a precision instrument on a 7-story, 350-ton, sophisticated telescope is
especially challenging because of the extremely intricate coordination required
to make all the systems work together seamlessly," said Herriot. Altair's
commissioning on Gemini is expected to be complete before the end of 2003.
A key feature
of Altair's sophistication is the ability to automatically monitor, adjust
and optimize multiple parameters during image exposures. The idea is to make
adaptive optics user-friendly for our community. When atmospheric conditions
allow, simply point and click and near diffraction-limited images are delivered
to a camera or spectrograph. Altair continually measures and reports on the
images' level of detail making it one of the most efficient adaptive optics
systems in the world. "By routinely delivering infrared images much sharper
than is currently possible even from space, Altair gives observers a tremendous
advantage in probing deeper in the universe and making more accurate measurements
of astronomical objects," Dr. Véran says.
enhances the quality and power of our imaging and spectroscopy," says Dr.
Matt Mountain, Gemini's Director. "Gemini will soon deliver diffraction-limited
images in the near-infrared." Gemini's theoretical diffraction limit (maximum
resolution) is about 40 milli-arcseconds in the near-infrared H-band (1.6
micrometers wavelength). At this point in commissioning, Altair can deliver
60-milli-arcsecond resolution in the H-band (60 milli-arcseconds is comparable
to viewing one grain of sand from about 1.6 kilometers or 1 mile away).
pointed out that Altair's commissioning means that one of the most sophisticated
adaptive optics system in the world is now built-in to Gemini North as a
facility instrument, and will soon be routinely available to all scientists
throughout the Gemini partnership.
"This is a major
achievement towards our Gemini goal of delivering space-quality images from
an 8-meter, ground-based telescope," said Dr. Mountain.
Director Dr. Jean-René Roy explains that Altair is a major step forward
in Gemini's aggressive plans to maximize the potential of adaptive optics
on ground-based astronomical imaging. Dr. Roy elaborates, "Altair, representing
the foundation of tomorrow's adaptive optics technology, is important for
the success of the next generation of 30- to 100-meter, diffraction-limited,
infrared, ground-based telescopes now on the drawing boards."
of adaptive optics technologies like these will undoubtedly revolutionize
ground-based astronomy. For now, Altair is state of the art and provides
a powerful new eye on the universe.
For more information, see the Adaptive Optics background information.
The Gemini Observatory
is an international collaboration that has built two identical 8-meter telescopes.
The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai`i
(Gemini North) and the Gemini South telescope is located on Cerro Pachón
in central Chile (Gemini South), and hence provide full coverage of both
hemispheres of the sky. Both telescopes incorporate new technologies that
allow large, relatively thin mirrors under active control to collect and
focus both optical and infrared radiation from space.
The Gemini Observatory
provides the astronomical communities in each partner country with state-of-the-art
astronomical facilities that allocate observing time in proportion to each
country's contribution. In addition to financial support, each country also
contributes significant scientific and technical resources. The national
research agencies that form the Gemini partnership include: the US National
Science Foundation (NSF), the UK Particle Physics and Astronomy Research
Council (PPARC), the Canadian National Research Council (NRC), the Chilean
Comisión Nacional de Investigación Cientifica y Tecnológica
(CONICYT), the Australian Research Council (ARC), the Argentinean Consejo
Nacional de Investigaciones Científicas y Técnicas (CONICET)
and the Brazilian Conselho Nacional de Desenvolvimento Científico
e Tecnológico (CNPq). The Observatory is managed by the Association
of Universities for Research in Astronomy, Inc. (AURA) under a cooperative
agreement with the NSF. The NSF also serves as the executive agency for the