1. Setting the declination factor

Recta compasses with declination correction are fitted with an adjusting screw, which allows you to adjust the easterly or westerly deviation. This screw is to be found on the reverse of the capsule. By turning this adjusting screw, the north marks are moved by the value of the declination in relation to the scale and the N-S grid lines on the compass capsule. Thus corrected, the north marks show the magnetic north while the scale and the N-S grid lines continue to display true north.



1 True north pole
2 Magnetic north pole
3 Deviation between the true and magnetic north poles = declination
4 Adjusting screw for declination correction
5 Screwdriver (supplied with the compass)

Procedure:

• In the case of a westerly declination
= turn the adjusting screw counterclockwise
• In the case of an easterly declination
= turn the adjusting screw clockwise
Once a value is set, it is fixed mechanically and cannot be changed unintentionally.



1 Westerly declination
2 Easterly declination



Note: The declination correction is especially important for globetrotters.


To check the local need to adjust declination online, please visit National Geophysical Data Center (NGDC) website.

2. The clinometer

The clinometer enables you to measure ascents or descents. Frequently it would be useful to know the gradient of a slope, road or mountainside. This decisionmaking aid can be of great importance for your safety (avalanche risk, capability of vehicles for handling slopes, etc.) and reduces the risk. With the aid of the conversion table (from degrees to per cent) on the reverse of the mirror, you can easily measure heights (trees, houses, mountains, etc.).



A. Lateral measurement
This application can be used to determine gradients of
slopes, which pass directly across the user’s field of view.
It should be noted that the result always represents an
average figure.

• Turn the reverse of the compass to face you, push in
  the mirror and block it with your finger.
• Place the compass directly across the field of view along the incline or sight the incline over the compass
  edge.
• The angle of inclination can be read off directly at the
  red mark on the red scale.

• Open out mirror and fix in position by light downward
  pressure.
• Tilt the compass to one side and sight the desired point
  along the upper long edge.
• Read off angle of inclination in the mirror (red mark on red scale).

The values read off can be converted to percentages with the aid of the conversion table on the reverse of the mirror (ascents, descents, difference of height, etc.).



1 Align the lower long edge of the compass
to the target to be sighted.
2 Read off the angle of inclination in degrees
directly on the scale.

3. Precision measurement of angles by prism optical system

The prism optical system (only fitted to model DP-10) brings a further dimension to the scope of the compass in the field of measurements. Basically, direct angle of measurement makes for more rapid handling, greater convenience and an even higher degree of accuracy. The resolution is to an accuracy of ± 0.3 degree! The compass is therefore suitable for use by professionals in fields such as ground surveying, road and pipeline construction, route location, etc.

Operation

• Adjust dial to approx. N = 0° or 180° (depending on
  whether you are working with your right or left hand).
• Bring the compass up to eye level and hold horizontally while sighting the target through the prism optical system. Adjust distance from eyes until the scale comes into focus through the lens.
• Take a sighting of the object along the line of the marking and read off the bearing (against magnetic north).




1 Sight the target
2 Prism optical system
3 Scale of the prism
optical system