Elementary astronomy; a beginner's text-book (1899)
Holden, Edward Singleton, 1846-1914 · New York, H. Holt and company · leaf 214
telescope ofhis own invention, and he had the benefit of accurateobservations of the planets made by Ttcho Brahe. Theopportunity for determining the true laws of the motions MOTIONS OF THE PLANETS—KEPLERS LAWS. 193 of the planets existed then as it never had before; andfortunately he was able,… … Fig. 125.—John Kepler,Born 1571, died 1630. determined by continuous observations of the planetscourse among the stars. The periodic times (the sidereal periods) of the planetswere known to Keplek from the observations of theancient astronomers. 194 ASTRONOMY. Mercuryrevolved about the Sun in about…
Astronomy
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