Great circle

Definition and stakes

Portrait of Denison Olmsted Denison Olmsted,  Letters on Astronomy

“ All great circles of the sphere cut each other in two points diametrically opposite, and consequently their points of section are one hundred and eighty degrees apart. A great circle, which passes through the pole of another great circle, cuts the latter at right angles. The great circle which passes through the pole of another great circle, and is at right angles to it, is called a secondary to that circle. ”
Source: Gutenberg

Portrait of George Biddell Airy George Biddell Airy,  Popular Astronomy: A Series of Lectures Delivered at Ipswich (1881)

“ You must understand what is meant by a great circle: it is a circle dividing the sphere into equal parts. Its plane therefore passes through the centre of the sphere. Now, our use of the celestial globe or sphere is founded on the assumption that it is a representation of the heavens, on the supposition that the eye of the observer is at the centre of the sphere. ”
Source: Wikisource

Parallax,  Zetetic astronomy: Earth not a globe… (1865)

“ But the pendulum must necessarily move in a ‘great circle,’ and hence to counteract its tendency to deviate into a ‘small circle,’ a correctory movement is constantly going on, to which the lengthening of the period necessary to complete a revolution must be ascribed. ”
Source: Gutenberg

Get perspective with Kwize: daily news enlightened by great literature