File:The elements of astronomy; a textbook (1919) (14779104051).jpg

Identifier: elementsofastro00youn (find matches)
Title: The elements of astronomy; a textbook
Year: 1919 (1910s)
Authors: Young, Charles A. (Charles Augustus), 1834-1908 Young, Anne Sewell, b. 1871., ed
Subjects: Astronomy Constellations
Publisher: Boston, New York (etc.) Ginn and Company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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time to time bodies very different from the starsand planets appear in the heavens, remain visible for someweeks or months, pnrsne a longer or shorter path, and thenvanish in the distance. These are the comets (from coma,i.e., hair,) so called because when one of them is brightenough to be seen by the naked eye, it looks like a star sur-rounded by a luminous fog, and usually carries with it astreaming tail of hazy light. The large ones are magnificentobjects, sometimes as bright as Venus and visible by day, witha head as large as the moon, having a train which extends fromthe horizon to the zenith, and is really long enough to reachfrom the earth to the sun. Such comets are rare, however.The majority are faint wisps of light, visible only with thetelescope. Fig. 89 is a representation of Donatis comet of 1858, which wasone of the finest ever seen. In ancient times comets were always regarded with terror, —as of evil omen, if not personally malignant; and the notion 371) COMETS. 265
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Fig. 89. — Naked-eye View of Donatis Comet, Oct. 4, 1858. (Bond.) still survives in certain quarters, although the most carefulresearch goes to prove that they really do not exert upon theearth the slightest perceptible influence of any kind. 266 DESIGNATION OF COMETS. (§ 371 Thus far, our lists contain nearly 800, about 400 of whichwere observed before the invention of the telescope, and there-fore must have been bright. Of those observed since then, onlya small proportion have been conspicuous to the naked eye, —perhaps one in five. The total number that visit the solarsystem must be enormous, for there is seldom a time when oneat least is not in sight; and even with the telescope we seeonly such as come near the earth and are favorably situatedfor observation. 372. Designation of Comets. — A remarkable comet generallybears the name of its discoverer, or of some one who has acquired its ownership, so to speak, by some important research concerning it.Thus we have Halleys, Enc

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