County Maps US

Tools Elevation, time and sun

Sun Position Calculator

For photographers, solar panels and anyone deciding which side of the house gets the afternoon light.

How to use it

  1. Type a place, pick a date and drag the time slider, in the place’s local time. "Now" jumps to the current moment there.
  2. Read the azimuth (compass direction), elevation (height above the horizon), and which way shadows fall and how long they are.
  3. Follow the sun’s path for the day on the sky dome: the centre is straight up, the rim is the horizon.
  4. The small world map marks the point where the sun is directly overhead at that moment.

How it works

The sun’s right ascension and declination are computed in your browser with the low-accuracy method in Jean Meeus’s Astronomical Algorithms (chapter 25), converted to azimuth and elevation for your coordinate with sidereal time, then corrected for atmospheric refraction, which lifts the sun by about half a degree at the horizon. Accuracy is a few hundredths of a degree, far finer than a compass can show.

Azimuth is measured clockwise from true north, not magnetic north; a hand compass needs the local magnetic declination applied. Shadow direction is the azimuth plus 180 degrees and shadow length is height divided by the tangent of the elevation. The subsolar point is the sun’s declination and the longitude where it is solar noon.

Questions

What do azimuth and elevation mean?
Azimuth is the compass bearing of the sun, 0 north, 90 east, 180 south, 270 west. Elevation is its angle above the horizon, 0 at sunrise and sunset and 90 straight overhead.
Which direction should solar panels face?
In the northern hemisphere the sun is due south at solar noon, so fixed panels usually face south at a tilt near the latitude; use the day path here to see how far the sun swings east and west in summer.
Is the sun ever directly overhead in the United States?
Only in Hawaii, which lies inside the tropics. Everywhere else the noon sun is south of the zenith; the elevation shown here tells you by how much.

All map tools, free and without an account. Location data is processed in your browser and by the open geocoding services named on the sources page; nothing is stored by this site.