The 6 fields and concepts you'll meet in the response — defined in plain English, each with a real example value.
The angle of the sun above the horizon, measured in degrees from 0° (horizon) to 90° (directly overhead).
Also called elevation angle or solar elevation. When the sun is below the horizon, altitude is negative. The maximum altitude depends on latitude and date—it's highest at solar noon on the summer solstice.
Examplealtitude: 45.2 (sun is 45.2° above horizon)
The compass direction of the sun measured in degrees from true north (0° = north, 90° = east, 180° = south, 270° = west).
Azimuth indicates which direction to face to see the sun. At solar noon in the Northern Hemisphere, azimuth is exactly 180° (due south). The sun rises with azimuth near 90° and sets near 270°, varying by season.
Exampleazimuth: 180.5 (sun is almost due south)
The angle between the sun and the point directly overhead (zenith). Zenith angle = 90° - altitude.
When the sun is directly overhead, zenith angle is 0°. At the horizon, zenith angle is 90°. This angle is often used in solar energy calculations because it directly relates to the intensity of sunlight hitting a horizontal surface.
Examplezenith: 44.8 (complementary to 45.2° altitude)
The moment when the sun reaches its highest point in the sky for a given location on a given day.
At solar noon, the sun is due south (Northern Hemisphere) or due north (Southern Hemisphere), and shadows point directly north or south. Solar noon rarely matches 12:00 clock time due to longitude within time zones and the equation of time.
ExamplesolarNoon: "12:15:30" (sun highest at 12:15:30 local time)
The length of a shadow cast by an object, determined by the sun's altitude angle.
Shadow length = object height × cot(altitude) = object height / tan(altitude). When the sun is at 45°, shadows equal object height. Lower sun angles create longer shadows. This calculation is essential for architectural shadow studies.
ExampleshadowLength: 1.5 (shadow is 1.5× object height)
The angle between the sun and the celestial equator, varying from +23.45° (summer solstice) to -23.45° (winter solstice).
Declination determines the sun's maximum altitude and the length of day for any latitude. It changes slowly throughout the year, being zero at the equinoxes. This value is key for calculating sun position at any location.
Exampledeclination: -23.1 (near winter solstice)
