PASCO SF-8619 MAGNETIC DIP NEEDLE - Manual

Instruction Sheet
for the PASCO
Model SF-8619
MAGNETIC DIP NEEDLE
012-04399C
3/95
$1.00
Introduction
This compass needle is used to measure the dip angle of
the Earth's magnetic field. However, it may also be used
in its horizontal position as a conventional compass.
Setup Procedure
➀
Assemble the two parts of the dip needle by inserting
the banana plug connector into the hole in the black
rod on the stand, as shown in equipment setup diagram.
➁
Put the dip needle in a location which is far away from
any ferromagnetic materials and other magnetic fields.
If you place the dip needle on a table, be sure there are
no ferromagnetic supports under the table top.
➂
Rotate the dip needle at its banana plug connection
until the plastic scale is in the horizontal plane.
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➃
While in the horizontal position, rotate the entire appa-
ratus to align the compass needle with the axis of ba-
nana plug pivot.
➄ Without changing the orientation of the base, rotate
the dip needle at its banana plug connection until the
plastic scale is in the vertical plane.
Theory
The dip needle is a magnetized steel needle which rotates
around its center of mass. When no other magnetic fields
are present, the dip needle will align itself along the direc-
tion of the Earth’s magnetic field. The dip angle, or incli-
nation, is the angle between the horizontal plane and the
total Earth magnetic field. By convention, the dip angle
is positive when pointing downwards.
The dip needle apparatus measures the angle,
θ
between
the vertical plane and the total Earth magnetic field. In
order to obtain the dip angle, subtract
θ
from 90˚.
The United States Geological Survey maintains a public
domain program for IBM compatible computers which
models geomagnetic parameters including dip angle. The
user inputs their latitude, longitude and elevation and the
program calculates the dip angle. Copies of the program
are free of charge and are available over the Internet via
the following methods:
ftp host: ftp.ngdc.noaa.gov login anonymous
gopher host: gopher.ngdc.noaa.gov no login necessary
www host: http://www.ngdc.noaa.gov no login necessary
The appropriate file is pcgeomag.zip which contains the
source code, executable and documentation files along
with the current magnetic field model.
Equipment Setup
© 1990 PASCO scientific
This instruction sheet written/edited by: Ann Hanks