A short course in astronomy and the use of the globes (1871)
Kiddle, Henry, 1824-1891 · New York, Chicago, Ivison, Blakeman, Taylor & co. · leaf 148
f where it crossed previously.The amount of precession is about 50 seconds every year,an entire revolution of the equinoxes requiring a periodof nearly 26,000 years. 244. This movement of the equinoxes is the result ofthe spheroidal form of the earth. For since the excessof matter at the equator is… … 243. What is precession ? What is its amount ? 244. How is it caused ? Explainby the diagram. 19 lJfi THE S TA R S. the rotation of the earth on its axis, is converted into asliding movement, as it were, of one circle upon theother, both preserving very nearly the same inclina-tion. This is…
Astronomy
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![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-162-91.webp)
