Lessons in astronomy including uranography. A brief intoductory course without mathematics (1896)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston, London, Ginn and company · leaf 125
HE SUNS ROTATION. [§162 162. The Suns Rotation. — Dark spots are often visibleupon the suns surface, which pass across the disc from east to west and indicate an axialrotation. The average timeoccupied by a spot in passingaround the sun and return-ing to the same apparent po-sition, as seen from… … Fig. 25. Synodic and Sidereal Revolutions of the Sun. suns disc at S ; while the sun rotates, E will also move forward in its orbit, and theobserver, the next time he sees the spot on the centre of thedisc, will be at E1, the spot having gone around the wholecircumference plus the arc SS. The…
Astronomy
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