Astronomy in a nutshell, the chief facts and principles explained in popular language for the general reader and for schools (1912)
Serviss, Garrett Putman, 1851-1929, Rouben Mamoulian Collection (Library of Congress) DLC · New York, London, G.P. Putnam's sons · leaf 303
e yourself to be facingnorthward. The hour when the observationis supposed to be made is, in every case,about 9 oclock in the evening, and the dateis about the first of the month. The top ofthe chart represents the sky a little belowthe zenith in the north, and the bottomrepresents the horizon in… … £pr< , aU Fig. 18. The North Circumpolar Stars. at the rate of about 30° per month. But thedaily rotation of the earth on its axis causesa similar westward motion of the heavens,at the rate of about 30° for every two hours.From this it results that on the same night, THe Constellations 245 after…
Astronomy
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