16 June 1999
PRELIMINARY INSTRUCTIONS FOR SURVEY OF THE COMPASS ROSE
The purpose of these instructions is to provide a standardized procedure
for making a magnetic survey of a compass swing area, using the MC-2 Compass
Calibrator. It is expected that the technical judgement be exercised through-
out the survey as it may require that methods be altered to fit the circum-
stances of a particular case.
DESCRIPTION OF COMMON PROCEDURES AND TERMS
1. Grid - A pattern of required test stations, laid out to cover the compass
2. Station - A grid point or hub mark at which magnetic readings will be
taken (See Grid Layout Sheet).
3. Set Up - When directed to set up over a station, precisely position the
tripod, with the required unit, directly over the station indicated by using
the plumb bob, and accurately level the unit.
4. Mark the Station - The precise point of the station may be marked with a
felt tipped pen, china marking pencil or any other method which will permit
set up to within two millimeters of the correct position. These marks may be
made directly on the hardstand, a piece of masking tape applied to the hard-
stand or on top and the face of a short 1X2 stake driven into the ground at
the proper position. These stations shall be accurately positioned by using a
steel tape to measure the distance between stations as determined. The dis-
tances between adjacent stations shall never exceed thirty (30) feet; however,
this distance can be reduced to allow more complete coverage of a particular
area. The marks shall be accurately aligned with the cross hairs of the
telescope by moving the telescope elevation ONLY.
5. Hub - Preferably a stake positioned at the north, south, east and west
points of the compass swing area, at a distance of approximately 300 feet from
the center. It shall be marked on the top of the stake as well as the face of
the stake toward the center.
6. Azimuth Control - Reference mark, preferably on a stake, positioned a
minimum of 300 feet in the north direction from the E-W line of the compass
swing area. It shall be marked on the face of the stake to allow accurate
alignment of the telescope cross hair when performing a setup for magnetic
1. To conduct a magnetic survey of a compass rose, it is first required that
a grid which will completely cover the area, be accurately laid out.
Enclosure (2) is the Grid Layout Procedure which gives step-by-step
instructions for laying out the grid using the MC-2 monitor. This procedure