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How to Calculate Azimuth

The azimuth of an object is its direction in the sky, measured in degrees. It corresponds to the cardinal direction on land, namely north (0 or 360 degrees), east (90 degrees), south (180 degrees) and west (270 degrees). Astronomers use azimuth and altitude (the height of an object above the horizon) to describe the location of a specific object. Because of the Earth's rotation, the azimuth and altitude both change over time as the stars appear to move across the night sky. Satellite dishes also use azimuth and altitude for pointing at the appropriate broadcasting satellites in the sky.

Things You'll Need

Compass

Instructions

- 1
  Use the compass to determine north. This gives you your "0" degree point for azimuth.
- 2
  Turn the compass to point in the direction with the azimuth you want to measure. The degree reading on the compass is your object's azimuth.
- 3
  If it is after dark, locate the North Star (Polaris) to calculate azimuth. The North Star is almost exactly due north, giving the star an azimuth of "0" degrees.
- 4
  Measure the distance, in degrees, between the North Star and your object. If the object is in the east, the distance to the east will equal your object's azimuth. For example, a star located 45 degrees east of due north has an azimuth of 45 degrees.
- 5
  For an object west of the North Star, the azimuth is 360 degrees minus the distance measured. Use the following formula to calculate azimuths to the west: Z = 360 - d, where "Z" is the azimuth you want to find, and "d" is the distance (in degrees) from due north. For example, if you measure a star to be 70 degrees from due north, its azimuth is 290 degrees (Z = 360 - 70 = 290).

Astronomy