Campbell TGT1, Operator'S Manual

Page: 52 / 64

Appendix G. Local Magnetic Declination
G-2
G.2 Prompts from GEOMAG
GEOMAG is accessed by calling 1-800-358-2663 with a computer and
telephone modem, and communications program such as TERM or GraphTerm
(PC208 Software). GEOMAG prompts the caller for site latitude, longitude,
and elevation, which it uses to determine the magnetic declination and annual
change. The following Menu and prompts are from GEOMAG:
MAIN MENU
Type
Q for Quick Epicenter Determinations (QED)
L for Earthquake Lists (EQLIST)
M for Geomagnetic Field Values (GEOMAG)
X to log out
Enter program option: M
Would you like information on how to run GEOMAG (Y/N)? N
Options:
1 = Field Values (D, I, H, X, Z, F)
2 = Magnetic Pole Positions
3 = Dipole Axis and Magnitude
4 = Magnetic Center
[1] : 1
Display values twice [N]: press return
Name of field model [USCON90]: press return
Date
[current date]:
press return
Latitude : 42/2 N
Longitude : 111/51/2 W
Elevation : 4454
Units (m/km/ft) : ft
Example of report generated by GEOMAG:
Model: USCON90 Latitude: 42/2 N
Date : 7/27/93 Longitude: 111/51/2 W
Elevation: 4454.0 ft
D
deg min
15 59.6
Annual change:
0 -6.1
The declination in the example above is listed as 15 degrees and 59.6 minutes.
Expressed in degrees, this would be 15.99 degrees. As shown in Figure G-1,
the declination for Utah is east, so True North for this site is 360 - 15.99, or
344 degrees. The annual change is -6.1 minutes.