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APOD

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

See Explanation. Clicking on the picture will download the highest resolution version available.

Four Lasers over Mauna Kea

Explanation: Are lasers from giant telescopes being used to attack the Galactic center? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some sky locations, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but many times no bright star exists in the direction where atmospheric information is needed. In these cases, astronomers create an artificial star where they need it -- with a laser . Subsequent observations of the artificial laser guide star can reveal information so detailed about the blurring effects of the Earth's atmosphere that much of this blurring can be removed by rapidly flexing the mirror. Such adaptive optic techniques allow high-resolution ground-based observations of real star s, planets , and nebulae . Pictured above, four telescopes on Mauna Kea , Hawaii , USA are being used simultaneously to study the center of our Galaxy and so all use a laser to create an artificial star nearby.

Date June 23, 2014
Credit Image Credit & Copyright: Jason Chu ( IfA Manoa)
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.