A short course in astronomy and the use of the globes (1871)
Kiddle, Henry, 1824-1891 · New York, Chicago, Ivison, Blakeman, Taylor & co. · leaf 63
dius-vector in different po-sitions of the planet. The planetmoves in its orbit so that thespaces A S B, B S C, etc., may beequal, if described in equal times.It has therefore to move muchfaster in the perihelion than in the aphelion, since at the former point the spaces must be wider in order to… … ELLIPTICAL, ORBIT. 72. What is the radius-vector of a planets orbit? What is perihelion? Aphe-lion ? What are the apsides ? 73. How does the velocity of a planet in its orbitvary ? When would it be uniform ? Why ? In the case of what bodies is this true ? OF THE PLANETS. 61 If the planets moved in…
Astronomy
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-192-110.webp)
