Supersharp images of the new adaptive optics VLT – ScienceDaily

The MUSE wide field mode coupled to GALACSI in ground layer mode corrects the effects of atmospheric turbulence up to one kilometer above the telescope over a relatively wide field of view. But the new narrow-field mode using laser tomography corrects almost all the atmospheric turbulence above the telescope to create much sharper images, but on a smaller area of ​​the sky [2].

With this new capacity, the 8-meter UT4 reaches the theoretical limit of image sharpness and is no longer limited by atmospheric blur. This is extremely difficult to achieve in the visible and gives images of a clarity comparable to those of NASA / ESA's Hubble Space Telescope. It will allow astronomers to study in a novel way fascinating objects such as supermbadive black holes in the center of distant galaxies, young star jets, globular clusters, supernovae, planets and their satellites in the world. solar system and much more.

is a technique to compensate for the blur effect of the Earth's atmosphere, also known as astronomical vision, which is a big problem faced by all ground telescopes. The same turbulence in the atmosphere that causes flickering of stars to the naked eye results in blurred images of the Universe for large telescopes. The light of stars and galaxies is deformed as it pbades through our atmosphere, and astronomers must use intelligent technology to artificially improve the quality of the image.

To achieve this, four bright lasers are attached to UT4 projecting columns of intense orange light 30 centimeters in diameter. in the sky, stimulating the sodium atoms in the atmosphere and artificially creating laser guide stars. Adaptive optics systems use the light of these "stars" to determine turbulence in the atmosphere and calculate corrections a thousand times per second, commanding the UT4's thin and deformable secondary mirror to constantly change its shape, correcting deformed light [19659003] MUSE is not the only instrument to benefit from the adaptive optics system. Another adaptive optical system, GRAAL, is already used with the HAWK-I infrared camera. This will be followed in a few years by the powerful new ERIS instrument. Together, these major developments in adaptive optics reinforce the already powerful fleet of ESO telescopes, highlighting the Universe.

This new mode is also a big step forward for ESO's Extremely Large telescope, which will need laser tomography to achieve its goals. scientific objectives. These results on UT4 with the AOF will help engineers and scientists at the ELT to move closer to implementing a similar adaptive optics technology on the 39 meter giant [19659003] Notes

[1] MUSE and GALACSI in Wide -Field mode already provides correction on a 1.0-minute field of view, with pixels of 0.2 by 0.2 second of arc. This new narrow field mode of GALACSI covers a field of view of 7.5 seconds much smaller arc, but with much smaller pixels, only 0.025 by 0.025 seconds of arcs to fully exploit the resolution exquisite.

[2] Atmospheric turbulence varies with altitude; some layers cause more damage to the light beam of stars than others. The complex adaptive optics technique of laser tomography aims to mainly correct the turbulence of these atmospheric layers. A set of predefined layers is selected for the MUSE / GALACSI narrow field mode at 0 km (bottom layer, always a major contributor) at 3, 9 and 14 km altitude. The correction algorithm is then optimized for these layers to allow astronomers to achieve an image quality almost as good as with a natural guide star and corresponding to the theoretical limit of the telescope .

Story Source:

ESO . Note: Content can be changed in style and length.