Close up of the Gemini South (GeMS)
laser which splits into 5 points to create a 'constellation' of guide stars for
improved corrections over a larger patch of sky. The points at the end of the
laser "columns" are where the laser light excites sodium atoms about
90 kilometers overhead and produces laser guide stars used for adaptive optics.
The visibility of the laser "columns" beneath the laser guide star
"constellation" is due to scattering of the laser's light by dust and
moisture in the lower atmosphere.
Publication-quality images and HD video available at: http://www.gemini.edu/node/12052. Credit: Gemini Observatory/AURA
Publication-quality images and HD video available at: http://www.gemini.edu/node/12052. Credit: Gemini Observatory/AURA
This image of the Orion Nebula Bullets
regions exemplifies the dramatic clarity (high resolution) that is achieved
with the GeMS adaptive optics system at the Gemini South telescope in Chile. In
this image, strong winds from violent explosions associated with a region of
star birth behind the Orion Nebula expel bullets of gas that created this
spectacular system of molecular hydrogen wakes. Researchers and Principal
Investigators John Bally and Adam Ginsberg of the University of Colorado used
GeMS data to determine the intensity of the blast and the nature of the
bullets. “Are they dense fragments of circumstellar disks? Could they be
ejected protoplanets? Or are they portions of the prestellar core from which
massive stars form?” Bally asks. “The Sub-arcsecond resolution provided by GeMS
is needed to resolve these shocks and to search for the compact, high-density
knots responsible for these wakes.”
Technical Data: Image, made from FeII, H2, and K-2.2 microns filters, were assigned the colors blue, orange, and white, respectively. The field-of-view is 2.9 x 3.8 arcminutes and is oriented with north up. The total (integrated) exposure time was 30 minutes cumulative for all filters and fields.
Image data from John Bally and Adam Ginsberg, University of Colorado. Color composite image by Travis Rector, University of Alaska Anchorage. Credit: Gemini Observatory/AURA
Full Resolution TIF (66.2MB) | Full Resolution JPG (27.1MB) | Med Resolution JPG (2.6MB)
Technical Data: Image, made from FeII, H2, and K-2.2 microns filters, were assigned the colors blue, orange, and white, respectively. The field-of-view is 2.9 x 3.8 arcminutes and is oriented with north up. The total (integrated) exposure time was 30 minutes cumulative for all filters and fields.
Image data from John Bally and Adam Ginsberg, University of Colorado. Color composite image by Travis Rector, University of Alaska Anchorage. Credit: Gemini Observatory/AURA
Full Resolution TIF (66.2MB) | Full Resolution JPG (27.1MB) | Med Resolution JPG (2.6MB)
“Celestial Pollution” from meteors like this weekend’s Perseid Meteor
Shower sprinkle sodium high up in our atmosphere and give astronomers
what they need to see the universe in much greater detail.
This weekend, as millions of people gaze up at the stars and wait for
Perseid meteors to streak across the sky, one would hardly think that
these awe-inspiring “shooting stars” are also a source of atmospheric
pollution.
However, meteors, like those from this month’s Perseid meteor shower,
burn up high in the Earth’s atmosphere leaving behind gases. “It’s a
form of natural pollution,” says Gemini Observatory’s Chad Trujillo who
heads up the facility’s state-of-the-art Adaptive Optics (AO) program.
This "pollution" doesn't actually pose a threat to humanity, (it's been
around for eons and seems to have had no adverse effect), but it's a
real boon to astronomers.
“One of the gases left behind by meteors is sodium, which collects in a
layer about 60 miles (90 kilometers) above the Earth,” says Trujillo
(see animation).
“The reason astronomers are so fond of this particular pollution layer
is because we can make it glow by using a sodium laser to excite this
sodium and produce temporary, artificial stars wherever we like. Believe
it or not,” jokes Trujillo, “there aren’t enough stars in the sky for
astronomers!”
Astronomers use these artificial stars, called laser-guide-stars, for AO
systems such as the latest technology at the Gemini South telescope in
Chile. AO allows scientists to see the universe with unprecedented
clarity.
The Perseid meteors are byproducts of Comet 109/Swift-Tuttle, which
leaves a trail of dust and ice behind when it passes by Earth’s orbit.
Each year, however, the Earth passes through the comet’s dust- and
ice-filled orbit. As it plows through that “debris,” it’s small
particles burn up in our atmosphere.
“Perhaps one person’s celestial ‘pollution’ is another’s ‘natural
resource,’” said Maria Womack, an astronomy program officer at the US
National Science Foundation (NSF). “It's this sodium layer, provided
courtesy of meteors like the Perseids, that astronomers use to get the
clearest views and understand the universe better.”
To celebrate this “happy marriage” of AO laser-guide-star technology and
natural meteor remains in Earth’s atmosphere, Gemini Observatory is
releasing a spectacular set of images illustrating laser guide stars,
including its newest technology which is part of its GeMS Adaptive
Optics system (GeMS stands for Gemini Multi-conjugate adaptive optics
System and is featured in a recent press release at: www.gemini.edu/node/12028).
The GeMS system uses five separate laser beams to create a
“constellation” of laser guide stars, (see top figure) which allows for
significantly better corrections than previous generations of AO
systems.
“The next generation of large ground-based telescopes will require
advanced AO systems like GeMS to work at their full-potential,” Trujillo
explains, “because as telescopes get bigger they must look through a
wider column of air. The wider the column of air, the more turbulence in
the air will distort the observed light. Using laser guide stars gives
us a reference so we can correct for that turbulence and see things with
amazing clarity from the ground.”
In addition to Gemini South, a laser guide star system is used at the Gemini North telescope on Mauna Kea in Hawai‘i (see images) and many major ground-based observatories worldwide.
Enjoy this year’s Perseid Meteor shower which peaks on the night of August 11-12; astronomers will!
Contacts:
- Chad Trujillo
Gemini Observatory, Hilo, Hawai‘i
Phone (Desk): (808) 974-2566
Email: ctrujillo@gemini.edu - Peter Michaud
Gemini Observatory, Hilo, Hawai‘i
Office: +1 (808) 974-2510
Cell: +1 (808) 936-6643
Email: pmichaud@gemini.edu - Antonieta Garcia
Gemini Observatory, La Serena, Chile
Phone (Desk): 56-51-2-205628
Cell: 09-69198294
Email: agarcia@gemini.edu
Publication-quality images and HD video available at: http://www.gemini.edu/node/12052
