Zenith - highest point overhead Horizon - edge or rim of the hemisphere Celestial Sphere- model of the sky
Location of celestial object: two measurements: Vertical Angledistance above horizon (Altitude). Horizontal Angle - distance around the horizon from some reference point (Azimuth)
Movements of Earth:
Revolution and Rotation
1- Orbit of Earth Elliptical or oval - shaped
2- Perihelion - closer to Sun - Jan 3rd - 147 million kIn
Aphelion- farthest - July 4th - 152 million Ian
(average distance earth to sun 150 million kIn)
3- Tilt 23.5 ° perpendicular (900) to the plane of tits orbit. Axis
point does not change, always points toward the North Star.
4- Amount of solar radiation heating earth depends on the angle at
which sun's rays strike. Equator greater solar radiation, poles
less intense
5- Summer solstice- June 21 or 22 - most daylight hrs. Sun's rays
strike Earth at 900 angle along the Tropic of Cancer.
6- Arctic circle 24 hours of weak daylight. Antarctic circle 24 hours
of darkness.
7- Winter solstice - Dec. 21 or 22 - Sun's rays - 900 angle along Tropic of Capricorn. Arctic circle have 24 hours of darkness, anarchic circle have 24 hours of daylight. .
8 -Autumnal Equinox- September 22 or 23 sun's ray strike- 900 angle along the equator. Equal daylight and darkness. March 21 or 22 - Vernal Equinox Earth- North Pole neither tilts neither toward nor away from Sun.
9- Apparent motion of Sun- East to West 12 noon is defined as the sun's highest in the sky. 24 Standard Time zones Earth rotates at 150 per hour.
10- International Date Line- North to South through Pacific
Ocean. Greenwich Mean Time (GMT) 00 longitude.
11- Earth's Magnetic Field - Magnetic North or South inclined at
11.50 to the rotational axis.