File:Elements of astronomy with explanatory notes, and questions for examination (1855) (14595930818).jpg

Identifier: elementsofastro00broc (find matches)
Title: Elements of astronomy ... with explanatory notes, and questions for examination
Year: 1855 (1850s)
Authors: Brocklesby, John, 1811-1889
Subjects: Astronomy
Publisher: New York, Farmer, Brace & co.
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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rsectionwith the ecliptic; but in the opposite quarter of theheavens, in the sign Libra. At the winter solstice, thesun is seen in the direction of the line OS1, but theearth has now so changed its position that this line fallssouth of the equator, making an angle with the latterof about twenty-three and one-half degrees, viz., S^L.The sun is now seen nearly twenty-three and one-halfdegrees south of the equator. We thus perceive thaton the supposition that the earth moves while the sun isstill, the sun appears on the equator at the time of thetwo equinoxes, about twenty-three and one-half de-grees to the north of it at the summer solstice, and abouttwenty-three and one-half degrees to the south at thewinter solstice. Could we follow the changes of theposition of the earths equator in respect to the eclipticthroughout every day in the year, we should find thatthese changes account satisfactorily for all the variations Explain from figure. suns apparent motion in declination, &c. 85
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86 THE EARTH VIEWED ASTRONOMICALLY, in the suns daily declination. The apparent motionof the sun in declination is, therefore, the result of theearths actual motion in her orbit. 132. Suns Apparent Motion in Eight AscensionExplained. If a person passes round a tree in anydirection, the tree, though immoveable, appears to movealong the distant horizon, following around after him atthe distance of half a circumference. In the same man-ner, the earth being in the sign Libra, the sun appearsin the opposite quarter of the heavens, at Aries; and asthe earth moves round the sun from Libra to Scorpio,Sagittarius, &ct, the sun also appears to follow roundin a circle from Aries, through Taurus, Gemini, &c.The real motion of the earth in her orbit then accountsfor the apparent motion of the sun in right ascension,from west to east. 133. The circular motion of the earth around the sunthus produces an apparent circular motion of the sun inthe heavens, and the apparent motion of the sun to

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