To adjust the telescope, artificial star

2002/02/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Astronomia

The main problem of telescopes from ground to space is the atmosphere. The particles present in this mass of gas affect light, so the stars are not clear. Telescopes aimed at stars therefore see undefined images that vibrate. Due to the high resolution of large telescopes, this effect is not serious with stars of high brightness, but those of low light do not give sharp images.

The problem is solved by moving the telescope, but it needs specific reference points. Now, laboratory engineers Lawrence Livermore have decided to artificially create this reference in California. To do this, an 18 watt laser has emitted a yellow beam up. In this way they can generate a point of light projected to 100 kilometers of the terrestrial surface, since it is reflected in the particles of the micrometeorites. This point is somewhat wider than that of a star.

This method has been used to adjust the Keck II telescope located on Mauna Kea Island in Hawaii. This telescope has a mirror that can change its appearance, constantly altered and taking as a reference the artificial star, the telescope could compensate for the distortions caused by the action of the atmosphere.