a) Equator to approximate- 

 ly 45° north & south 

 latitude . 



b) About 30 to 90° north & 

 south latitude. 



Accuracy: ±0.1 milligal. 



2. North American gravi- 

 meter 



Total range: 1, 000 milligals 

 (can be used worldwide 

 by resetting) . 



3. LaCoste and Romberg 

 gravimeter 



MAGNETISM 



Vector airborne miagnetometer 

 Types 2A and 2B (Naval 

 Ordnance Laboratory) 



Total field: 23, 000 to 



78, 000 gammas. 

 Accuracy: ±0. 05%. 

 Inclination: -90 to +90°. 

 Accuracy: *0.1°. 

 Magnetic heading: to 360°. 

 Accuracy: ±0.1°. 

 Relative Bearing (Astro): 



to 360°. 

 Accuracy: ±0. 1°. 



Marine navigational aid 



magnetometer (Varian free 

 nuclear precision magneto- 

 meter, model XN-4901) 



Land magnetic stations 



Fuska field magnetometer 



Total field: 25, 000 to 



73, 000 gamnnas. 

 Accuracy: ±0.003% or 

 ±0.5 gamma. 



Magnetic dip: 90° N. to 90° 



s. ± r. 



Magnetic meridian: to 360° 



±r arc. 

 True meridian: to 360° 



±r arc. 

 LOG MH: ±0.001. 

 LOG H/M: ±0.001. 



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