The document discusses different coordinate systems used to locate celestial objects, including: 1. The equatorial coordinate system uses right ascension and declination, analogous to longitude and latitude, with right ascension measured eastward from the vernal equinox and declination measured from the celestial equator. 2. The horizon coordinate system uses altitude and azimuth but coordinates change for the same object in different locations or times. 3. Other systems discussed include the ecliptic, galactic, and local coordinate systems based on an observer's meridian and hour angles.