The Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s Very Large Telescope (VLT) has achieved the first light with a new adaptive optics mode called laser tomography and captured super-sharp images of Neptune and other objects.
This image of Neptune was obtained during the testing of the Narrow-Field adaptive optics mode of the MUSE/GALACSI instrument on ESO’s Very Large Telescope. Image credit: ESO / P. Weilbacher, AIP.
Adaptive optics is a technique to compensate for the blurring effect of the Earth’s atmosphere, also known as astronomical seeing, which is a big problem faced by all ground-based telescopes.
The same turbulence in the atmosphere that causes stars to twinkle to the naked eye results in blurred images of the Universe for large telescopes.
Light from stars and galaxies becomes distorted as it passes through our atmosphere, and astronomers must use clever technology to improve image quality artificially.
The image of Neptune on the left was obtained during the testing of the Narrow-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. Image credit: ESO / P. Weilbacher, AIP / NASA / ESA / M.H. Wong & J. Tollefson, UC Berkeley.
ESO astronomers can now use their new technique to correct for turbulence at different altitudes in the atmosphere and capture images from the ground at visible wavelengths that are sharper than those from the NASA/ESA Hubble Space Telescope.
“MUSE now has two adaptive optics modes: the Wide Field Mode and the Narrow Field Mode,” they said.
“The MUSE Wide Field Mode coupled to an adaptive optics unit called GALACSI in ground-layer mode corrects for the effects of atmospheric turbulence up to one km above the telescope over a comparatively wide field of view.”
“But the new Narrow Field Mode using laser tomography corrects for almost all of the atmospheric turbulence above the telescope to create much sharper images, but over a smaller region of the sky.”
With this new capability, the 8-m VLT Unit Telescope 4 reaches the theoretical limit of image sharpness and is no longer limited by atmospheric blur.
