A text-book of general astronomy : for colleges and scientific schools (1888)
Young, Charles A. (Charles Augustus), 1834-1908 · Boston ; London : Ginn & Company · leaf 201
duration of the spots is very various, but,astronomically speaking, they are always short-lived phenomena,sometimes lasting for only a few days, more frequently, perhaps, fora month or two. In a single instance, a spot has been observedthrough as many as eighteen successive revolutions of the sun.… … Fig. 105. — Distribution of Sun Spots in Latitude. beyond the latitude of 45°. Fig. 105 shows the distribution of sev-eral thousand spots as observed b}- Carrington and Sporer. Occasionally, what Trouvelot calls veiled spots are seen beyondthe 45° limits — grayish patches surrounded by faculae,…
Astronomy
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