Astronomy in a nutshell, the chief facts and principles explained in popular language for the general reader and for schools . e are drawnthrough the poles of the ecliptic and per-pendicular to the ecliptic itself. Themeridian of celestial longitude that passesthrough the two equinoxes is the eclipticprime meridian. This intersects the equi-noctial colure at the equinoctial points,making with it an angle of 23^°. Thesolstitial colure, which it will be rememberedruns round the celestial sphere half-waybetween the equinoxes, is perpendicularto the ecliptic as well as to the equator, andso is com
Astronomy in a nutshell, the chief facts and principles explained in popular language for the general reader and for schools . e are drawnthrough the poles of the ecliptic and per-pendicular to the ecliptic itself. Themeridian of celestial longitude that passesthrough the two equinoxes is the eclipticprime meridian. This intersects the equi-noctial colure at the equinoctial points,making with it an angle of 23^°. Thesolstitial colure, which it will be rememberedruns round the celestial sphere half-waybetween the equinoxes, is perpendicularto the ecliptic as well as to the equator, andso is common to the two systems of passes alike through the celestial polesand the poles of the ecliptic. It will alsobe observed that the vernal equinox is com-mon to the two systems of co-ordinates, be-cause it lies at one of the intersections of theecliptic and the equator. In passing from onesystem to the other, the astronomer employsthe methods of spherical trigonometry. 10. The Zodiac and the Precession of theEquinoxes. The next thing with which wemust make acquaintance is the zodiac. THe Zodiac and Equinoxes 51. Na Fig. 4. The Ecliptic and Celestial Latitude and Longitude. C, as in the other figures, is the place of the observer andZ is the zenith, but to avoid complication of details thecircle of the horizon is not drawn, only the north-and-south line, N C S, being Eq is the Ec is the and P are the celestial poles,p and p are the poles of the is the nadir. V is the vernal equinox, and A the autumnal circle through s, parallel to the ecliptic, is a latitudecircle. The circle p s p is the ecliptic meridian of the star circle P V P A is the equinoctial circle p V p A is the prime ecliptic arc of the ecliptic meridian contained between theecliptic and s measures the stars arc of the ecliptic contained between V and thepoint where the ecliptic meridian psp meets theecliptic (
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Keywords: ., bookcentury1900, bookdecade19, booksubjectastronomy, bookyear1912
