what is the purpose of the event horizon telescope
Event Horizon Telescope The Event Horizon Telescope (EHT) is a project to create a large telescope array consisting of a global network of radio telescopes and combining data from several very-long-baseline interferometry (VLBI) stations around the Earth. The aim is to observe the immediate environment of the Milky Way's supermassive black hole Sagittarius A*, as well as the even larger black hole in Messier 87, with angular resolution comparable to the black hole's event horizon.[1][2][3][4][5]
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]