Perigee (per´i-jē). That point in the orbit of the sun or moon in which it is at the least distance from the earth.
Perihelion (per-i-hē´li-on). That part of the orbit of a planet or comet in which it is at its least distance from the sun.
Plan´et. The name given to a few bright and conspicuous stars which are constantly changing their apparent situations in the celestial sphere.
Precession (pre-sesh´un) of the Equinoxes. A continual shifting of the equinoctial points from east to west.
Radius Vector. An imaginary line joining the center of the sun and the center of a body revolving about it.
Retrocession (rē-tro-sesh´un) of the Equinoxes. The going backward of the equinoctial points.
Sagittarius (saj-i-tā´ri-us). One of the twelve signs of the zodiac, which the sun enters about November 22.
Sat´ellite. A small planet revolving round another planet.
Scor´pio. The eighth sign of the zodiac, which the sun enters about October 23.
Selenography (sel-en-og´raf-i). The description of the surface of the moon.