The Laser Guide Star of the Very Large Telescope (VLT) at the European Southern Observatory in northern Chile.
(Image Sources: Wikipedia.org, By G. Hüdepohl/ESO - http://www.eso.org/public/images/gerd_huedepohl_2/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=10980623)
By Glenn A. Walsh
Reporting for SpaceWatchtower
An Adaptive Optics Laser, being pioneered by the European Southern Observatory, is expected to greatly improve the sharpness of stellar images observed by ground-based telescopes. To do this, the Observatory and its commercial partners have developed a laser three times more powerful than the lasers currently used at astronomical observatories.
The problem that the European Southern Observatory (ESO) is trying to solve is the same problem that has vexed ground-based astronomers for hundreds of years. Atmospheric turbulence, which is what causes stars to appear to “twinkle” in the sky, has always made it more difficult for astronomers to study the composition and behavior of such stars, particularly dim and very distant stars.
To ameliorate this twinkling effect, astronomers have used nearby stable stars, brighter and often closer stars of which more information is known, to calibrate their telescopes. However, in many cases, such nearby stable, reference stars do not exist.
So, researchers have hit on the solution of creating artificial stars to help calibrate their telescopes. These artificial stars are created by using a laser to blast sodium atoms at a height of 55.9 statute miles / 90 kilometers in the atmosphere.
Such a laser, known as the Four Laser Guide Star Facility, already operates at the European Southern Observatory's Very Large Telescope (VLT) array, located on Cerro Paranal in the Atacama Desert of northern Chile. This laser, which currently has a strength of 22 watts, has been essential to the success of the VLT.
However, in order to create an even more stable, artificial guide star, ESO has now increased the new laser's power to 63 watts, nearly three times the power of the VLT laser. This more powerful laser comes from a Raman fiber amplifier laser source, developed by an ESO commercial partner, a Canadian company called MPB Communications.
Additional new technology, to assist with this Adaptive Optics Laser, has been developed by a German company, TOPTICA Photonics Ag. This company specializes in frequency “chirping,” which allows a laser to bounce back and forth between several frequencies. This provides larger bandwidths and more excited sodium atoms, and hence, brighter artificial stars to use for telescope calibration.
The Adaptive Optics Laser was tested at the Allgaeuer Volkssternwarte Ottobeuren Observatory in Germany, in August. This new laser will first be installed at the European Space Agency's (ESA) Optical Ground Station in Tenerife, Spain, which is a research and development (R&D) collaboration between the European Southern Observatory and the European Space Agency.
This new laser can also help with satellite communications. Atmospheric turbulence can also disrupt some of the newer laser systems in-use between satellites and ground stations. The Adaptive Optics Laser, with the greater power, may allow much better data transfer from satellites to ground stations. This will also be tested at the ESA facility in Spain.
Internet Links to Additional Information ---
Laser Guide Star: Link >>> https://en.wikipedia.org/wiki/Laser_guide_star
European Southern Observatory (ESO):
Link 1 >>> https://www.eso.org/
Very Large Telescope, European Southern Observatory: Link >>> https://en.wikipedia.org/wiki/Very_Large_Telescope
European Space Agency (ESA):
Link 1 >>> https://www.esa.int/
Thursday, 2021 October 7.
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Glenn A. Walsh, Informal Science Educator &
Link >>> http://buhlplanetarium2.tripod.com/weblog/spacewatchtower/gaw/
Electronic Mail: < email@example.com >
Project Director, Friends of the Zeiss: Link >>> http://buhlplanetarium.tripod.com/fotz/
SpaceWatchtower Editor / Author: Link >>> http://spacewatchtower.blogspot.com/
Formerly Astronomical Observatory Coordinator & Planetarium Lecturer, original Buhl Planetarium & Institute of Popular Science (a.k.a. Buhl Science Center), Pittsburgh's science & technology museum from 1939 to 1991.
Formerly Trustee, Andrew Carnegie Free Library and Music Hall, Pittsburgh suburb of Carnegie, Pennsylvania.
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh: Link >>> http://www.planetarium.cc Buhl Observatory: Link >>> http://spacewatchtower.blogspot.com/2016/11/75th-anniversary-americas-5th-public.html
* Adler Planetarium, Chicago: Link >>> http://adlerplanetarium.tripod.com
* Astronomer, Educator, Optician John A. Brashear: Link >>> http://johnbrashear.tripod.com
* Andrew Carnegie & Carnegie Libraries: Link >>> http://www.andrewcarnegie.cc
* Other Walsh Authored Blog & Web-Sites: Link >>> https://buhlplanetarium.tripod.com/gawweb.html