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ESO's Very Large Telescope Now Delivers Images Sharper Than Hubble (eso.org)
ffkom shares an excerpt from a press release via the European Southern Observatory: ESO's Very Large Telescope (VLT) has achieved first light with a new adaptive optics mode called laser tomography -- and has captured remarkably sharp test images of the planet Neptune, star clusters and other objects. The pioneering MUSE instrument in Narrow-Field Mode, working with the GALACSI adaptive optics module, can now use this new technique to correct for turbulence at different altitudes in the atmosphere. It is now possible to capture images from the ground at visible wavelengths that are sharper than those from the NASA/ESA Hubble Space Telescope. The combination of exquisite image sharpness and the spectroscopic capabilities of MUSE will enable astronomers to study the properties of astronomical objects in much greater detail than was possible before.
Only partially true. Space-telescopes still have an advantage in some area's, especially for the deep and near-infrared wavelengths, and ultraviolet wavelengths, but the other advantages are becoming less and less obvious, especially if you consider the cost of both space-based as Earth-based telescopes.
The disturbances of the atmosphere - the major drawback (diffraction limit) up until the last decade of the 20th century - have become largely reduced thanks to adaptive optics and other technological advances.
The argument that we are now capable of constructing space-telescopes that are better than Hubble has no bearings on the comparative advances, since we can also create better earth-based telescopes than VLT, these days. As the Extremely Large Telescope will show, no doubt. There is little doubt this latter one will exceed the JWST, just as the VLT did with Hubble - IF the JWST was going for the visible light waves, which it isn't. In fact, it's the main reason Beryllium mirrors were used that excel in infra-red wavelengths, about the last advantage space-telescopes still have that warrant the vastly more expensive cost (now at more than 10 *billion* for the JWST, if I remember correctly).
Note that for that price, you could have made 10 Overwhelmingly Large Telescopes (OWL) which would completely DWARF the JWST on almost all other fronts, certainly when using interferometry.
--- "To pee or not to pee, that is the question." ---
IIRC the mirror was ground with gravity present. Then under zero G conditions it sprung back to an unanticipated shape.
No, Perkin-Elmer simply screwed up. And amazingly after finishing a 72-inch mirror and sending it into high orbit, they didn’t think of running the Foucault figure test that every amateur astronomer who has ever ground a mirror knows To do.