Live and act
John Hadley became a Fellow of the Royal Society on March 21, 1717 . He found methods for grinding aspherical telescope mirrors , which enabled him to build the first powerful Newtonian telescope in 1721 . With its precise 15 cm parabolic mirror , it proved to be superior to a lens telescope of the same size. But he also built Gregory telescopes .
In 1731 he invented the octant , the forerunner of the sextant . In navigation and as a device for measuring star heights, it soon replaced the Davis quadrant used up until then .
His brothers George (1685–1768) and Henry (* 1687) were involved in the construction of the telescope as well as the octant, which was first named "Quadrant" .
The Mons Hadley , the Mons Hadley Delta and the Hadley groove on the moon, in the immediate vicinity of which the Apollo 15 lunar module landed, are named after John Hadley . In Graham Land in Antarctica, the Hadley Upland is named after him.
John Hadley was the oldest of George Hadley and Katherine Fitzjames' 6 children. His younger brother, George Hadley , became a well-known meteorologist and discovered the Hadley cells of the atmospheric circulation.
Hadley married Elizabeth Hodges in 1734. They had one child, John, born in 1738.
His nephew John Hadley (1731–1764), son of Henry, chemist and doctor, member of the Royal Society from 1758.
- EGR Taylor: The mathematical practitioners of Hanoverian England 1714-1840 . Cambridge 1966
|BRIEF DESCRIPTION||English astronomer and mathematician|
|DATE OF BIRTH||April 16, 1682|
|PLACE OF BIRTH||Barnet , Hertfordshire|
|DATE OF DEATH||February 14, 1744|
|Place of death||Barnet , Hertfordshire|