Guy's Elements of Astronomy, and an Abridgment of Keith's New Treatise on the Use of the Globes
by Joseph Guy
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from ... Show synopsis This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1848 Excerpt: ...the equator, and are used in the elevation of the poles. _ 6. Great Circles divide the globe into two equal parts, as the equator, ecliptic, and the colures. 7. Small Circles divide the globe into two unequal parts, as the tropics, polar circles, parallels of latitude, 8. Meridians, or Lines of Longitude, are semicir cles, extending from the north to the.south pole, and cutting the equator at right angles. Every place upon the globe is supposed to have a meridian passing through it, though there be only 24 drawn upon the terrestrial globe; the deficiency is supplied by the brass meridian. When the sun comes to the meridian of any place (not within the polar circles, ) it is noon or midday at that place. 9. The First Meridian is that from which geographers begin to count the longitudes of places. In English maps and globes the first meridian is a semicircle supposed to pass through London, or the royal observatory at Greenwich. 10. The EauATOH is a great circle of the earth, equidistant from the poles, and divides the globe into two hemispheres, northern and southern. The latitudes of places are counted from the equator, northward and southward, and the longitude of places are reckoned upon it, eastward and westward. The equator, when referred to the heavens, is called the equinoctial; because when the sun appears in it, the days and nights are equal all over the world, viz. 12 hours each. The declinations of the sun, stars and planets, are counted from the equinoctial northward and southward, and their right ascensions are reckoned upon it eastward round the celestial globe from 0 to 360 degrees. 11. The Ecliptic is a great circle in which the sun makes his apparent annual progress among the fixed stars; or it is the real path of the earth round the sun, and..