Sunpath

Sunpath refers to the apparent trajectory of the sun across the sky as observed from a specific location on Earth. It is determined by the observer’s latitude, the time of year, and the time of day, and can be affected by atmospheric refraction. A sunpath is typically depicted on a sunpath diagram or solar path chart, which plots the sun’s position using solar altitude (elevation above the horizon) and solar azimuth (the compass direction along the horizon). The sun traces a curved arc from sunrise on the eastern horizon to sunset on the western horizon, reaching its highest point at solar noon. The exact arc varies with latitude and season: near the equator the sun can rise almost vertically and reach high elevations, while at higher latitudes the arc is shallower and daylight duration changes more with the seasons. In polar regions, the sun’s path can be very low in the sky or stay above the horizon for extended periods in summer and disappear in winter.

Sunpath information is used in architecture, urban planning, and solar energy to analyze daylight availability, shading, and the orientation and tilt of buildings or solar collectors. Designers apply fixed or tracking systems to optimize exposure; a common guideline for fixed installations is to tilt surfaces roughly at an angle related to latitude, while trackers continuously adjust to follow the sun’s arc through the day. Calculations of sunpath positions typically involve solar declination, hour angle, and the resulting altitude and azimuth.