| A | B |
|---|
| Astronomy | The study of the universe and all the objects in it (it's also your favorite class!) |
| Verbal Description | One way you could explain to someone your location. |
| Latitude | the angular distance north or south of the equator |
| Equator | the starting point for measuring latitude in the terrestrial system (0°) |
| Celestial Sphere | the bowl of night! |
| Only one hemisphere | the amount of the Celestial Sphere that is visible at any given time |
| 10° | the measurement of the approximate distance across your fist |
| width across your finger | approximately measures 2° |
| width across your hand outstretched | approximately measures 10° |
| Horizon System | uses the coordinates of Altitude and Azimuth |
| arbitrary | how the zero point is selected in a coordinate system |
| zenith | the point located directly over your head |
| azimuth | the side to side coordinate in the Horizon system |
| coordinates change with time and location | the disadvantage in the horizon system |
| 4 minutes | how long it takes the sky to move 1° |
| Polaris | located 3/4° from the north celestial pole |
| Celestial North Pole | located 3/4° from Polaris above the earth's north pole |
| counterclockwise | the direction the earth rotates on its axis |
| 41.5° | the altitude of Polaris in the night sky in Cleveland, Ohio (it's also our latitude) |
| ecliptic | the path the sun follows through the sky |
| meridian | the line on the celestial sphere that connects the Celestial North Pole to the Celestial South Pole and crosses through the Zenith |
| Equatorial system | uses the coordinates of Declination and Right Ascension |
| Right Ascension | the side to side coordinate in the Equatorial System |
| Local hour angle | what you must know to make the coordinates useful in the Equatorial system |
| Tropic of Capricorn | located at 23.5° S Latitude |
| Antarctic Circle | located at 66.5°S Latitude |
| South Pole | Located at 90° S latitude |
| 66.5°N | location of the Arctic Circle |
| 23.5°N | location of the Tropic of Cancer |
| 90°N | location of the North Pole |
| Axial Parallelism | describes why the earth always points the same direction at all positions in our orbit |
| Winter Solstice | Occurs on December 21 marking the first day of winter |
| year | measurement of time based on our revolution around the sun |
| sidereal day | used by astronomers...measures the length of time it takes a star to return to the meridian |
| tropical year | length of time for the earth to complete on complete seasonal cycle |
| synodic period | length of time between intervals of a planets retrograde motion |
| highlands | the mountainous regions on the moon's surface |
| albedo | refers to the amount of reflected light |
| synchronous rotaiton | describes that the moon is both rotating and revolving at the same rate |
| conjunction | occurs at new moon phase when the moon and the sun are both on the same side of the earth |
| wanderer | planet means this in greek |
| retrograde | describes the apparent backward motion of a planet in the nighttime sky |
| terrestrial coordinate system | uses latitude and longitude to locate positions on the earth's surface |
| zero point | where you start counting in a coordinate system (for the terrestrial system it's the equator and prime meridian) |
| longitude | the side to side coordinate in the terrestrial system |
| prime meridian | the zero point for longitude |
| bowl of night | what we call the celestial sphere |
| 2° | approximate measure of the width across your finger |
| 20° | approximate measure from the tip of your pinky to the tip of your thumb when you hand is outstretched |
| across your knuckles | measures approximately 10° |
| great circles | cuts a sphere into 2 equal halves; also what all coordinate systems are based on |
| celestial horizon | located 90° from the zenith in all directions; basis for the horizon system |
| altitude | the up down coordinate in the Horizon system |
| simplicity | advantage of the Horizon system |
| 1° | how far the sky moves every 4 minutes |
| diurnal circle | the daily path of a star in the sky...we only ever see 1/2 of this at a time |
| north circumpolar cap | portion of the sky in the northern hemisphere that is always visible |
| celestial south pole | no star is located here...directly over the south pole |
| 1/2 to 1/3 | for the majority of the continental US...this is how far up from the horizon you look for Polaris |
| zodiac | name for the group of constellations that lie along the ecliptic |
| 23.5° | tilt of the earth's axis |
| celestial equator | located 90° from each celestial pole and passes through the zenith (perpendicular to the Meridian) |
| declination | the up down coordinate in the Equatorial system |
| coordinates don't change | the advantage in the equatorial system |
| Tropic of Cancer | located at 23.5° N latitude |
| Arctic Circle | located at 66.5°N latitude |
| North Pole | located at 90°N latitude |
| 0° | latitude location of the equator |
| 66.5°S | location of the Antarctic Circle |
| 23.5°S | location of the Tropic of Capricorn |
| 90°S | location of the South Pole |
| Summer Solstice | first day of the season of summer |
| Day | unit of time based on the rotation of the earth |
| Apparent solar day | measured from high noon to high noon |
| sidereal year | one true revolutionary period for the earth |
| reflected light | albedo measures this |
| lowlands | also referred to as the maria |
| nodes | the points of intersection of the moon's plane of orbit and the earth's |
| opposition | full moon phase when the moon and sun are on opposite sides of the earth |
| quadrature | technical names for when the earth-sun-moon form a 90° angle |
| prograde | the direct or forward motion of a planet in the night sky |
