The geography of the heavens, and class-book of astronomy: (1858)
Burritt, Elijah H. (Elijah Hinsdale), 1794-1838, Mattison, Hiram, 1811-1868 · New York, Mason brothers · leaf 174
THE SUN HIS DISTANCE, MAGNITUDE, ETC. 173 … rarely visible to the naked eye, frequently pass over his disc,from east to west, in the period of nearly fourteen days. These spots are usually surrounded by a spots on thb sck. penumbra, or less deeply shaded border,and that, by a margin of light more bril-liant that that of the Sun. A spot…
Constellations · Stars
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