How to Calculate Change in Latitude
Latitude is an angular measurement that indicates your north-south position on Earth. You can calculate your latitude relatively easily simply by measuring the angle of a known celestial object above the horizon. Measuring latitude is a much easier task than measuring longitude, which requires you to accurately measure the time.
Instructions
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1
Learn the lines of latitude. The equator has a latitude of 0 degrees, the north pole has a latitude of 90 degrees North and the South Pole has a latitude of 90 degrees south. A latitude of 45 degrees north would therefore be any position on the Earth that's exactly halfway between the equator and the North Pole.
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2
Locate the North Star (Polaris) on the night that you wish to measure your initial latitude. This star forms the end of the handle in the Little Dipper, which stays close to the more easily identified Big Dipper. Polaris is useful because it's always within one degree of the North Pole and therefore provides a direct measurement of the latitude.
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3
Measure the angle of Polaris above the horizon. Several devices can measure the angle of a celestial object, including a sextant. Other instruments can measure this angle, depending on the accuracy you require.
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4
Use the angle that you obtained in step 3 as your north latitude for your starting position. Take a second measurement of the angle of Polaris on a subsequent night as your final latitude. The difference between these two measurements will provide your change in latitude.
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5
Determine the change in your north-south position. Each degree of latitude represents 69 miles, so you can multiply the difference in latitude (in degrees) by 69 to get the north-south distance traveled in miles.
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References
- Photo Credit California State University
