| A | B |
|---|
| Parsec | The distance an object is if it shows a 1 arc second parallax shift |
| Parsec | 3.26 light years |
| Light year | The distance light travels in a year |
| Light year | A measurement of distance used in the Universe |
| Astronomical Unit (A.U.) | The average distance from the Sun and Earth |
| Astronomical Unit (A.U.) | A means of measurement within the solar system |
| Solar noon | When the Sun is on the meridain |
| Solar day | The time period from solar noon to the next solar noon |
| Sidereal day | Earth's rotation with respect to the stars not the Sun |
| Meridian | An imaginary line running from nort |
| Zenith | The point directly above the observer |
| Celestial pole | Earth's axis extended into space |
| Ecliptic | The Sun's path against the backdrop of stars |
| Zodiacal constellations | The constellaions found 18 degrees on either side of the ecliptic |
| Ecliptic | The plane of orbit between Earth and the Sun |
| Celestial Equator | Earth's equator extended into space |
| Declination | The measurement that indicates how far an object is north or south of the celestial equator |
| Right Ascension | The measuremet that indicates how far an object is east or west of the Sun's location at the instant of the vernal equinox |
| Rotation | The movement of Earth that produces the apparent motion of objects in the sky |
| Revolution | The movement of Earth that produces the seasonal nature of the constellations |
