Celestial Objects-A natural object which is located outside of Earth's atmosphere, such as the Moon, the Sun, an asteroid, planet, or a star.
Arc- a continuous portion of a circle
Constellation-A group of stars forming a recognizable pattern that is traditionally named after its apparent form or identified with a mythological figure.
Apparent daily motion- Objects in the sky appear to rise in the East and set in the West each day. This apparent daily motion is a reflection of the Earth's rotation about its axis.
Apparent solar day-The duration of one rotation of the earth on its axis with respect to the apparent sun.
Earth revolution-the orbit of the Earth around the sun
Earth Rotation-the rotation of the solid Earth around its own axis
Focault pendulum-a freely swinging pendulum that consists of a heavy weight hung by a long wire and swings in a constant direction which appears to change showing that the earth rotates
Coriolis Effect-the deflection of objects or substances (such as air) moving along the surface of the Earth, rightward in the Northern Hemisphere and leftward in the Southern Hemisphere.
Seasons-Each of the four divisions of the year (spring, summer, autumn, and winter) marked by particular weather patterns and daylight hours, resulting from the earth's position which is changing with regard to the sun Perpendicular and Direct Solar rays- Direct rays are when the Sun’s light hits the specified part of the Earth that you are observing at a direct angle of 90 degrees.This means that the sun’s rays are perpendicular to the earth.
Perihelion and aphelion-The points nearest and farthest from the sun in the orbit of a planet or other celestial body.
Local noon- Noon at the local meridian
Zenith position-The point on the celestial sphere that is directly above the observer.
Equinox-Either of the two times during a year when the sun crosses the celestial equator and when the length of day and night are approximately equal
Tropic of Cancer-the circle of latitude on the Earth that marks the most northerly position at which the Sun may appear directly overhead at its zenith.
Summer solstice-the day of the year when the Sun is above the horizon for the longest amount of time, around 21st June in the northern half of the Earth and 21st December in the southern half.
Tropic of Capricorn-a line of latitude located at about 23 degrees south of the equator
Winter solstice-the solstice that marks the start of winter, at the time of the shortest day
Orbit -the curved path of a celestial object or spacecraft around a star, planet, or a moon
Focus-the origin of an earthquake
Eccentricity- the deviation of a curve or orbit from circularity
Orbital Velocity- the orbital speed of a body, generally a planet or a natural satellite, is the speed at which it orbits around the center of a system, usually around a massive body.
Harmonic Law of Planetary Motion-a law stating that the ratio of the square of the revolutionary period (in years) to the cube of the orbital axis (in astronomical units) is the same for all the planets
Astronomical unit- A unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of our sun
Gravitation-Movement toward a center of attractive force, as in the falling of bodies to the earth
Inertia-A tendency to remain unchanged
Energy Transformation-the amount of work which may potentially be done by forces or velocities within a system
Sidereal month-The time it takes the moon to orbit once around the earth with respect to the stars
Phases of Moon-A phase of the moon is the appearance of the illuminated portion of the Moon as seen by an observer on Earth
Synodic- Relating to or involving the conjunction of stars, planets, or other celestial objects
Lunar month-A month measured between successive new moons