Free Astronomy Magazine September-October 2018

37 SEPTEMBER-OCTOBER 2018 SPACE CHRONICLES ondary mirror of UT4 to constantly alter its shape, correcting for the distorted light. MUSE is not the only instrument to benefit from the Adaptive Optics Facility. Another adaptive optics system, GRAAL, is already in use with the infrared camera HAWK-I. This will be fol- lowed in a few years by the powerful new in- strument ERIS. Together these major develop- ments in adaptive optics are enhancing the al- ready powerful fleet of ESO telescopes, bring- ing the Universe into focus. This new mode also constitutes a major step forward for the ESO’s Extremely Large Telescope, which will need Laser Tomography to reach its science goals. These results on UT4 with the AOF will help to bring ELT’s engi- neers and scientists closer to implementing similar adaptive optics technology on the 39- metre giant. T he image of the planet Neptune on the left was obtained during the testing of the Nar- row-Field adaptive optics mode of the MUSE instrument on ESO’s Very Large Telescope. The image on the right is a comparable image from the NASA/ESA Hubble Space Telescope. Note that the two images were not taken at the same time so do not show identical surface features. [ESO/P. Weilbacher (AIP)/NASA, ESA, and M.H. Wong and J. Tollefson (UC Berkeley)] atoms high in the atmosphere and creating artificial Laser Guide Stars. Adaptive optics systems use the light from these “stars” to deter- mine the turbulence in the atmos- phere and calculate corrections one thousand times per second, com- manding the thin, deformable sec- passes through our atmosphere, and astronomers must use clever technology to improve image qual- ity artificially. To achieve this four brilliant lasers are fixed to UT4 that project columns of intense orange light 30 centimetres in diameter into the sky, stimulating sodium ! [ESO/S. Kammann (LJMU)] NGC 6388