Using the equations on the previous page, the position of the sun in the sky can be determined from the observer's location and the time of day. In the top blue squares, enter the observer's location and time of day.

Time and Date

The time is given as 24 hour time and the minutes are entered separately. Thus for 5:15 pm, enter 17 in the hour box and 15 in the minute box.

Longitude, Latitude and Time Zone (GMT)

Longitude, latitude and time zone of locations throughout the world are available at www.timeanddate.com. Minutes of longitude and latitude are entered as fractions, so 17° 30' becomes 17.5. Enter locations with an east longitude as negative. For daylight saving (summer time), subtract 1 hour from the given values. Generally speaking, locations east of Greenwich (UK) are positive and locations west of Greenwich are negative.

The graph on the right shows the position of the sun's azimuth and elevation angles projected onto a two-dimensional plane. An elevation angle of 90° corresponds to the stage when the sun is directly overhead and appears in the centre of the graph. An elevation angle of 0° corresponds to the point when the sun is on the horizon, and appears on the outer edge of the graph. The azimuth angles are marked around the graph's edge, so an azimuth angle of 0° is at the top of the graph. The graph is best understood by trying a number of times and locations and seeing where the azimuth and elevations are plotted.

Explanation of polar plots

The most convenient way to plot the sun's position throughout the day is on a polar plot. Click on the animation for an explanation of these polar plots.