| www.tmatlantic.com
Test & Soldering Equipment On-line Store |
|
D.E.V.I.C.E. (Wiki)Calculators Services |
|||||
Filter by first letter
|
Hadley, John
John Hadley was born on April 16, 1682. He was an English mathematician, and laid claim to the invention of the octant. In 1730 Hadley invented the reflecting octant, which could be used to measure the altitude of the sun or other celestial objects above the horizon at sea. A mobile arm carrying a mirror and pivoting on a graduated arc provides a reflected image of the celestial body overlapping the image of the horizon, which is observed directly. If the position of the object on the sky and the time of the observation are known, it is easy for the user to calculate his own latitude. An American, Thomas Godfrey, independently invented the octant at approximately the same time. Hadley also developed ways to make precision aspheric and parabolic objective mirrors for reflecting telescopes. In 1721 he showed the first parabolic Newtonian telescope to the Royal Society. Citing www.wikipedia.org |
|