NorthStar 957, Operator'S Manual, Page: 187 / 204

957 Operator’s Manual, Rev. B Page 179
identifier 9960 (Northeast US) indicates that the gap between
the start of any two adjacent master signals is 99,600
microseconds long.
HDOP
H
orizontal
D
ilution of
P
recision.
heading
The compass direction toward which the longitudinal axis of a
vessel points.
knot
One nautical mile per hour.
latitude
Imaginary lines on the earth's surface running East/West and
expressed in degrees (0-90) north or south of the Equator.
Used with the North/South lines of longitude to determine
position.
leg
The line, or path, between any two adjacent waypoints in a
route.
leg-up
An orientation of the
CHART
screen in which the viewing
angle matches your desired track when navigating, on a
leg-by-leg basis.
longitude
Imaginary lines on the Earth's surface running North/South
and expressed in degrees (0-180) east or west of the Prime
Meridian (a line running from the North to South Pole, passing
through Greenwich, England).
Loran-C
LO ng RA nge N avigation. A system of land-based radio
transmitters emitting precisely timed pulses that are received
and translated into position “fixes” by a loran receiver. The 957
can convert and display its GPS coordinates into Loran-C
position measurements, or TDs.
loran chain
A group of loran transmitters comprising a master station and
at least two secondary stations.
loran receiver
An electronic position finding device that receives pulses from
loran stations.
magnetic variation
The difference between magnetic North and true North. Since
the difference varies according to geographic location, the
Northstar 957 automatically calculates magnetic variation and
uses it to display bearings as magnetic north. The variation at
any location changes slowly over a period of years, and the
unit compensates, according to the current calendar year.