Herschel, John F. W. (John Frederick William), Sir, 1792-1871 · London : Longman, Rees Orme · leaf 156
which isnothing more than an altitude and azimuth instrument,this reduction is made in the very act of reading off the telescope of the theodolite, it is true, is pointed in suc-cession to P, and Q; but the readings off of its azimuthcircle give —not the angle P A Q between the directionsof the… … horizontal angles. Let E be /Q the center of the earth; A,B, C, the places on its sphe-rical surface, to which threestations, A, P, Q, in a coun-try are referred by radii EA, EBP, EC Q. If a the-odolite be stationed, at A, theaxis of its horizontal circlewill point to E when trulyadjusted, and its…
Astronomy
Internet Archive · York University Libraries · Public Domain Mark 1.0. Free to use for anything.
