A text-book of general astronomy : for colleges and scientific schools (1888)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston ; London : Ginn & Company · leaf 242
triaugles OED and ECa, OD : Ea : : OE : EC or /. OD is the dif-ference between the radii of the sun and the earth, = R — r.Ea = r: and OE is the distance of the earth from the sun = A. Hence 1= A x(——^ = ——A. \E - rj 108.5 (The fractional factor is constant, since the radii of the sun and PENUMBRA.… … Fig. 124. — Dimensions of the Earths Shadow. garding the earth as a perfect sphere and taking its mean radius.This length varies about 14,000 miles on each side of the mean asthe earth changes its distance from the sun. The semi-angle of the cone (the angle ECb, or ECB in the figure) isfound as…
Astronomy
Internet Archive · Wellesley College Library · Public Domain Mark 1.0. Free to use for anything.
