Appendix A. Determining True North and Wind Sensor Orientation
A-2
Declination angles east of True North are considered negative, and are
subtracted from 360 degrees to get True North as shown FIGURE
360° are the same point on a compass). Declination angles west of True North
are considered positive, and are added to 0 degrees to get True North as shown
For example, the declination for Longmont, CO (10 June 2006) is 9.67
°
, thus
True North is 360
°
─ 9.67
°
, or 350.33
°
as read on a compass. Likewise, the
declination for McHenry, IL (10 June 2006) is ─2.68
°
, and True North is
0
°
─ (─2.68
°
), or 2.68
°
as read on a compass.
FIGURE A-2. A declination angle east of True North (positive) is
subtracted from 360 (0) degrees to find True North
FIGURE A-3. A declination angle west of True North (negative) is
subtracted from 0 (360) degrees to find True North
