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SKU 42433 For technical questions please call 1-800-444-3353. Page 5
Measuring a Horizontal Angle
1. To measure a horizontal angle, adjust the Mirror so that when you look into the Mirror you
see the Front Sight.
2. Move the Compass around until the Sighting Line is lined up with the tip of the Front Sight
and with the object you are sighting. The Compass is now aligned.
3. Read and note the position of the Needle. This will give you an accurate reading to 1 degree.
4. Sight a second object the same way as in steps 1,2 and 3. The difference in the azimuths
obtained by the two sights is the angle between the lines from you, the observer, to the two
objects. For instance, if object one is at 280 degreess and object 2 is at 170 degrees,
the angle is 280-170 = 110 degrees.
Measuring an Angle with the Compass Firmly Supported
1. Use this method only if the Compass is firmly supported. Open the Compass up
completely. Look through the aperture near you to the tip of the far Sight. Line up the object
in these sights. The Compass is now aligned.
2. Making certain that the Compass does not move, move your eye away from the Sights and
note the measurement on the Compass.
Measuring a Vertical Angle
Azimuths
The direction of a line can be specified by its azimuth, the angle the north end ot the compass’
horizontal projection makes with north (magnetic or true), measured clockwise from 0 degrees to
360 degrees.
Located in the lower half of the Compass are an index and Vernier that can be rotated by an arm on
the outside of the Compass case. Also there is a Bubble Level, and a Circular Level. Finally, there
are two scales. The inner one measures in degrees to + or - 90
o
. The outside scale measures in
percent grade, from 0% to 100%.
1. Sight from the Front Sight thorugh the small hole in the Mirror. Adjust the Mirror so that you
can see the Frame and the Bubble Level.
2. Move the Lever so that the Bubble Level is centered while you are sighting the desired
object.
3. Note the reading on the Scales.
Estimating the Inclination of a Line
The inclination of a line can be estimated by opening the Compass all the way up. Line up the edge
of the case with the line that you want to estimate the inclination of. Move the lever until the Level
Bubble is centered. Note the reading.