Leica MX400 Operating Instructions Manual page 218

Glossary
The phantom Loran-C Time Differences used in the navigator
are based on mathematical models. Local deviations in propa-
gation speed and Additional Secondary Factors (ASF) are not
included. The calculated positions may therefore differ from
positions obtained by dedicated Loran-C receivers by several
hundred meters.
MAGNETIC DEVIATION
The error introduced into the steering compass reading by
nearby ferrous metal mass distorting the earth magnetic flux
field surrounding the compass.
MAGNETIC HEADING
Direction, as sensed by the steering compass, in relation to
magnetic north.
MAGNETIC NORTH
Direction in the plane of the observer's horizon toward the
earth's north magnetic pole.
MAGNETIC VARIATION
The angle by which magnetic north varies from true north at any
given point on the earth's surface. This value is automatically
added to the magnetic heading input to provide true heading for
calculation and display purposes.
MENU
A list of functions in the display.
Selection of a function from the list is accomplished with either
the toggle key or the soft keys.
MERCATOR CHART
A map developed by Mercator projection, wherein the curved
surface of the earth's ellipsoid is projected onto a cylinder and
the cylinder is "unwrapped" to form a flat representation of the
ellipsoid.
MERIDIAN
The circumference line of a meridian plane. The meridians
define longitude. A special case meridian is the Greenwich
meridian, whose longitude is 0 degrees and to which all other
meridians are referenced.
Version 3.3
Operator's Manual
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