Identifier: astronomyforuseo00gill (find matches)Title: Astronomy for the use of schools and academiesYear: 1882 (1880s)Authors: Gillet, J. A. (Joseph Anthony), 1837-1908 Rolfe, W. J. (William James), 1827-1910Subjects: AstronomyPublisher: New York : Potter, Ainsworth, & Co.Contributing Library: The Library of CongressDigitizing Sponsor: The Library of CongressView Book Page: Book ViewerAbout This Book: Catalog EntryView All Images: All Images From BookClick here to view book online to see this illustration in context in a browseable online version of this book.Text Appearing Before Image:Fig. 420. year, and from age to age; and hence they have comeuniversally to be denominated as fixed. It is, however, nowwell known that the stars, instead of being really stationary,are moving at the rate of many miles a second; but theirdistance is so enormous, that, in the majority of cases, itwould be thousands of years before this rate of motionwould produce a sufficient displacement to be noticeableto the unaided eye. 366 ASTRONOMY. 364. Secular Displacement of the Stars.—Thoughproper motion of the stars is apparently slight, it will,the course of many age% produce a marked change in theconfiguration of the stars. Thus, in Fig. 420, the left-handportion shows the present configuration of the stars ofthe Great Dipper. The small arrows attached to the starsshow the direction and comparative magnitudes of theirmotion. The right-hand portion of the figure shows theseText Appearing After Image:Fig. 421. stars as they will appear thirty-six thousand years from thepresent time. Fig. 421 shows in a similar way the present configura-tion and proper motion of the stars of Cassiopeia, andalso these stars as they will appear thirty-six thousand yearshence. Fig. 422 shows the same for the constellation Orion. 365. The Secular Motion of the Sun. — The stars in allparts of the heavens are found to move in all directionsand with all sorts of velocities. When, however, the motions ASTRONOMY. & of the stars are averaged, there is found to be an apparentproper motion common to all the stars. The stars in theNote About ImagesPlease note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.