Astronomy for the use of schools and academies (1882) (14763857682)

Identifier: astronomyforuseo00gill (find matches)

Title: Astronomy for the use of schools and academies

Year: 1882 (1880s)

Authors: Gillet, J. A. (Joseph Anthony), 1837-1908 Rolfe, W. J. (William James), 1827-1910

Subjects: Astronomy

Publisher: New York : Potter, Ainsworth, & Co.

Contributing Library: The Library of Congress

Digitizing Sponsor: The Library of Congress

Text Appearing Before Image:

re Fcectinditatis, Mare Nectaris, Mare Tran-quillitatis, Mare Serenitatis, Mare Imbrium, Ma7-e Frigoris,and Oceanus Procellarum. All these plains can easily be rec-ognized on the surface ofthe full moon with the un-aided eve. 113. The Terminator of the Moon. — Theterminator of the moonis the line which sepa-rates the bright and darkportions of its disk.When viewed with atelescope of even mod-erate power, the termi-nator is seen to be veryirregular and uneven.Many bright points areseen just outside of theterminator in the darkportion of the disk, whileall along in the neigh-borhood of the termi-nator are bright patchesand dense shadows. These appearances are shown in Figs.131 and 132, which represent the moon near the first andlast quarters. They indicate that the surface of the moonis very rough and uneven. As it is always either sunrise or sunset along the termi-nator, the bright spots outside of it are clearly the tops ofmountains, which catch the rays of the sun while their bases

Text Appearing After Image:

Fig. 131. u6 ASTRONOMY. are in the shade. The bright patches in the neighborhoodof the terminator are the sides of- hills and mountains whichare receiving the full light of the sun, while the denseshadows near by are cast by these elevations. 114. Height of the Lunar Mountains.—There are twomethods of finding the height of lunar mountains : —

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1882

Library of Congress

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public domain