when was the hubble space telescope launched by space shuttle discovery
Hubble Space Telescope Hubble is the only telescope designed to be serviced in space by astronauts. After launch by Space Shuttle Discovery in 1990, five subsequent Space Shuttle missions repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments. The fifth mission was initially canceled on safety grounds following the Columbia disaster (2003). However, after spirited public discussion, NASA administrator Mike Griffin approved the fifth servicing mission, completed in 2009. The telescope is operating as of 2018[update], and could last until 2030â€“2040.[3] Its scientific successor, the James Webb Space Telescope (JWST), is scheduled for launch in March 2021.[8]
Halley's Comet Halley's 1986 apparition was the least favourable on record. The comet and Earth were on opposite sides of the Sun in February 1986, creating the worst viewing circumstances for Earth observers for the last 2,000 years.[94] Halley's closest approach was 0.42 AU.[95] Additionally, with increased light pollution from urbanization, many people failed to even see the comet. It was possible to observe it in areas outside of cities with the help of binoculars.[96] Further, the comet appeared brightest when it was almost invisible from the northern hemisphere in March and April.[97] Halley's approach was first detected by astronomers David Jewitt and G. Edward Danielson on 16 October 1982 using the 5.1Â m Hale telescope at Mount Palomar and a CCD camera.[98] The first person to visually observe the comet on its 1986 return was amateur astronomer Stephen James O'Meara on 24 January 1985. O'Meara used a home-built 24-inch telescope on top of Mauna Kea to detect the magnitude 19.6 comet.[99] On 8 November 1985, Stephen Edberg (then serving as the Coordinator for Amateur Observations at NASA's Jet Propulsion Laboratory) and Charles Morris were the first to observe Halley's Comet with the naked eye in its 1986 apparition.[100][101]