Getting to Know Your Compass

Its Purpose!

v   To Point North: The red arrow points north.  If you know north, you can find any other direction.  (More details later.)

ITS PARTS!

v   Base – The rectangular clear plastic piece on the bottom

v   Bezel – The round movable part with ________ printed on it

v   Needle – The part that does not move (in theory) when you turn the rest of the compass.  It points north!

Its Peculiarities!

v   It Doesn’t Quite Point North: The compass actually points to the magnetic north pole, which, in the Eastern United States, is west of the true North Pole.  In Charlottesville, the difference is about 9 degrees.  This difference, known as declination, varies +/- 5 degrees in the ASRC response area and increases as you move east

v   Sometimes it Doesn’t Point North at All: The compass responds to the earth’s magnetic field.  Other things produce magnetic fields, generally electricity and large chunks of iron.  Vehicles, power lines and big rocks (which contain iron) are common culprits.

More Practice Questions

4.         What is the Distance between North gayton church and the house due east at ~ B1516?

5.          What is the elevation difference between these two points?

6.          If you were standing at the summit of Hazel mountain (~A1225) and your compass said you were facing due north, in what direction would you actually be gazing?  (Give a number)