Sunrise - the instant at which the upper edge of the Sun appears over the horizon in the morning (center of sun 0.83° below horizon)
Sunset - the disappearance of the Sun below the horizon (center of sun 0.83° below horizon)
Daylight - (1) time between sunrise and sunset
Civil Twilight - (2) the horizon is clearly defined. Sun rays reflected in Earth's atmosphere. Sky color: bright yellow and orange. Artificial lighting is not required. (0.83-6° below horizon)
Nautical Twilight - (3) sailors can no longer rely on the horizon to guide them (6-12° below horizon)
Astronomical Twilight - (4) sky illumination is so faint that it is practically imperceptible. (12-18° below horizon)
Night - (5) altitude of the Sun is 18° below horizon
Example: Twilight, Sunrise
Solar noon - moment when Sun is at highest point in the sky (altitude). In most locations, not at 12:00.
Altitude (Sun) - angle of the sun relative to the Earth's horizon (0°=center of sun is at horizon.)
Azimuth (Sun) - Compass direction of the Sun, relative to North (0°=North, 180°=South, 90°=East, 270°=West)
View angle - angular diameter of the Sun.
Diameter of the Sun: DSun = 1 391 400 km = 864 576 mi
Distance: Earth ↔ Sun (Center-to-center)
Distance City ↔ Sun (nearest point)
Latitude: Geographic coordinate that specifies the north–south position of a point on the Earth's surface. Angle between equator and location. (-90° = south pole, 0 = equator, +90 = north pole)
Longitude: A geographic coordinate that specifies the east-west position of a point on the Earth's surface. Angle between prime meridian and location (-180..180°)
GMT(*) = Difference from Greenwich Mean Time in hours. Example:
sun .5deg.com
Sunrise - the instant at which the upper edge of the Sun appears over the horizon in the morning (center of sun 0.83° below horizon)
