John Hadley

John Hadley (* 16. April 1682 in Barnet, heart-Ford-almost; † 14. February 1744 in Barnet) was an English astronomer and mathematician.

Hadley became 21. March 1717 Fellow of the Royal Society. It developed 1721 the first efficient Newton telescope.

1731 it invented the Oktanten, the forerunner of the sextant.

Both at the building of the telescope and first „quadrant the “Oktanten mentioned were its brothers George (1685-1768) and Henry (*1687) takes part; they were three of six children of the George Hadley and the Katherine Fitzjames.

Of the same name:
His nephew John Hadley (1731 - 1764), son of the Henry, chemist and physician, member of the Royal Society starting from 1758.


  • EH Taylor: The mathematical practitioners OF Hanoverian England 1714-1840. Cambridge 1966


  > German to English > (Machine translated into English)