How to Calculate Azimuth
Yes, it's spherical trigonometry – but it's not rocket science! Azimuth is simply the angle of an object in the sky along the horizon.
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You Will Need
- The latitude and longitude of starting point
- The latitude and longitude of the celestial object
- A calculator with sine, cosine, and arcsine functions
- A chart or map (optional)
- A GPS device (optional)
Steps
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Step 1
Determine latitude and longitude
Determine the latitude and longitude of the starting point, or observation point, from which you'll calculate the angle. Use L to represent the starting point latitude.
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Find latitude and longitude by going to the location with a GPS device.
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Step 2
Find object's coordinates
Find the latitude and longitude of the celestial object. Use D to represent the latitude of the point on the earth where the desired object is straight overhead.
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Step 3
Find t
Find the meridian angle, represented by t, also known as the local hour angle – or LHA. It is the difference between the observer's longitude and the longitude of the celestial object.
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Step 4
Calculate the altitude
Calculate the altitude of the object, called H. Multiply the sine of L by the sine of D. Then multiply the cosine of L by the cosine of D, by the cosine of t. Add these two products and determine the arcsine of the sum.
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Step 5
Compute azimuth
Find the azimuth angle, Z, by multiplying the cosine of D by the sine of t, and dividing the product by the cosine of H. Then determine the arcsine of the result, which will give you the azimuth angle.
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The distance between Earth and our moon is, on average, 238,900 miles.
