ESO, P. WEILBACHER/AIP, NASA, ESA, M.H. WONG AND J. TOLLEFSON/UC BERKELEY
A new technology developed for the the Very Large Telescope in Chile lets the ground-based observatory take visible light images of the planet Neptune (left) which rivals the images taken from the Hubble Space Telescope (right) in clarity. The technology works by cancelling out blur from Earth's atmosphere which is allowing astronomers to focus like never before.
Facts about the Very Large Telescope and Hubble Space Telescope:
Very Large Telescope (VLT), an observatory located on the mountain Cerro Paranal (2,635 metres [8,645 feet]) in Chile and consisting of four telescopes with mirrors 8.2 metres (27 feet) in diameter and four others with mirrors 1.8 metres (5.9 feet) in diameter. These telescopes can operate individually or together as an interferometer that functions like a telescope with a mirror 200 metres (600 feet) in diameter. The large telescopes are named Antu, Kueyen, Melipal, and Yepun, which are the names for the Sun, the Moon, the Southern Cross, and Venus in the language of the Mapuche people. Construction of the VLT began in 1991, and its first observations were made in 1998. Among the VLT’s notable discoveries are the first direct spectrum of an extrasolar planet, HR 8799c, and the first direct measurement of the mass of an extrasolar planet, HD 209458b. The VLT also discovered the most massive star known, R136a1, which has a mass 320 times that of the Sun. The VLT is operated by the European Southern Observatory, an astrophysical research organization supported by 16 European countries.
Hubble Space Telescope (HST), the first sophisticated optical observatory placed into orbit around Earth. Hubble was launched into orbit on April 24, 1990, some 13 years after its construction was approved. It was serviced and updated by space shuttle crews in 1997, 1999, 2002, and 2009. Earth’s atmosphere obscures ground-based astronomers’ view of celestial objects by absorbing or distorting light rays from them. A telescope stationed in outer space is entirely above the atmosphere, however, and receives images of much greater brightness, clarity, and detail than do ground-based telescopes with comparable optics.
The HST is a large reflecting telescope whose mirror optics gather light from celestial objects and direct it into two cameras and two spectrographs (which separate radiation into a spectrum and record the spectrum). The HST has a 2.4-metre (94-inch) primary mirror, a smaller secondary mirror, and various recording instruments that can detect visible, ultraviolet, and infrared light. The most important of these instruments, the wide-field planetary camera, can take either wide-field or high-resolution images of the planets and of galactic and extragalactic objects. This camera is designed to achieve image resolutions 10 times greater than that of even the largest Earth-based telescope. A faint-object camera can detect an object 50 times fainter than anything observable by any ground-based telescope; a faint-object spectrograph gathers data on the object’s chemical composition. A high-resolution spectrograph receives distant objects’ ultraviolet light that cannot reach Earth because of atmospheric absorption.
References
https://www.britannica.com/topic/Hubble-Space-Telescope
https://www.britannica.com/topic/Very-Large-Telescope
https://www.sciencenews.org/article/move-over-hubble-sharp-pic-neptune-was-taken-earth