Christ's College Library, Cambridge - John Hadley, English mathematician, was born #OTD in 1682. He laid claim to the invention of the octant in 1730, although the American, Thomas Godfrey independently invented
![An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . C 1 Fi Q. IV An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . C 1 Fi Q. IV](https://l450v.alamy.com/450v/2awt4m2/an-account-of-a-catadioptrick-telescope-made-by-john-hadley-esq-frswith-the-description-of-a-machine-contrivd-by-him-for-the-applying-it-to-use-phlwiwnixljjpiv-2awt4m2.jpg)
An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . C 1 Fi Q. IV
![An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . 37^.51.-^. FlG.111 Stock Photo - Alamy An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . 37^.51.-^. FlG.111 Stock Photo - Alamy](https://l450v.alamy.com/450v/2awt55b/an-account-of-a-catadioptrick-telescope-made-by-john-hadley-esq-frswith-the-description-of-a-machine-contrivd-by-him-for-the-applying-it-to-use-c-1-fi-q-iv-iigtk-iltslurtfctup-2awt55b.jpg)
An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . 37^.51.-^. FlG.111 Stock Photo - Alamy
![An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . IX# Anatomm Philof.T»-ans .l.^y6.^^. X An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . IX# Anatomm Philof.T»-ans .l.^y6.^^. X](https://c8.alamy.com/comp/2AWT6C2/an-account-of-a-catadioptrick-telescope-made-by-john-hadley-esq-frswith-the-description-of-a-machine-contrivd-by-him-for-the-applying-it-to-use-ix-anatomm-philoft-ans-ly6-x-ig-i-3751-philtrans07963102-2AWT6C2.jpg)
An Account of a Catadioptrick Telescope, Made by John Hadley, Esq; FRSWith the Description of a Machine Contriv'd by Him for the Applying It to Use . IX# Anatomm Philof.T»-ans .l.^y6.^^. X
![2014] candy dejesus: Telescopes: en, eyepiece, focus, galileo, hadley, invention, inventors, kepler, mirror, newton | Glogster EDU - Interactive multimedia posters 2014] candy dejesus: Telescopes: en, eyepiece, focus, galileo, hadley, invention, inventors, kepler, mirror, newton | Glogster EDU - Interactive multimedia posters](https://d3208a.medialib.edu.glogster.com/gIGfC8AH5U8AtW3thRC7/thumbnails/gI/gIGfC8AH5U8AtW3thRC7-6jj825j9r7qlv57b9qvt2b0/1416597359-source.jpg)