Magnetic North and Geographic North: Declination Adjustment
"Geographic North" is the Earth's axis of rotation. It is the point where the meridians on a map converge. "Magnetic North" refers to the point on the Earth's surface that attracts its magnetic field downward. Therefore, Magnetic North does not exactly correspond to Geographic North, and its location is constantly changing. The difference between Magnetic North and Geographic North is called "Declination" or "Variation." The Kestrel 4500, like all other compasses, will indicate Magnetic North. However, Geographic North can be displayed by simply setting the Variation for your location. By selecting the Magnetic North Direction mode, the screen will display "Magnetic North" under the indications. By selecting the Geographic North Direction mode, the screen will display "N#.# E geographic" at the variation setting location.
Kestrel 4500:
To switch between these modes, press the (-) button. Then use the < and > buttons to toggle between Magnetic and Geographic. To enter the variation based on your location, scroll through the suggestions until Variation is highlighted, then use the < and > buttons to set the value.
Kestrel 5500:
On the Direction screen, use the middle button to reach the settings and after highlighting "mode," use your left/right arrows to switch from Magnetic to Geographic. To enter the variation for your location, press until Variation is highlighted below, then set the value.
How to Enter the Variation/Declination
These values for your location can be obtained online. The NOAA website is an excellent resource for this kind of information: www.ngdc.noaa.gov. To find the Variation value for your location in the United States by your postal code, go to the NOAA website, "Calculate Your Declination" page.