WeatherMaster A Instruction Manual - page 11
12.5 Compass Mode -
Magnetic Declination
12.4 Compass Mode -
Applications of the Compass
12.6 Compass Mode -
Magnetic Declination Compensation
12.7 Compass Mode -
Magnetic Declination at Major Cities
What is Magnetic Declination
!
!
! The angular difference between Magnetic North Pole
and True North Pole is called magnetic declination. Its
m a g n i tu d e ( d e g re e s a n d m i n u te s ) a n d d i r e c ti o n
(easterly and westerly) depend on where you are in the
world.
!
! The Watch also includes a compensation setting for
Magnetic Declination. Check the coming section
"
for more details.
Magnetic Declination Information
! Most topographic maps include a small arrow which
s h o w s t h e m a g n e t i c n o r t h p o l e a n d m a g n e t i c
declination information.
! For the benefit of the user, this manual includes the
magnetic declinations for some major cities. Check the
coming section 'Magnetic Declination at Major Cities'
for more details.
! For those cities, their names are not included on the
list, please check the online magnetic declination
information at:
1.http://www.geolab.nrcan.gc.ca/geomag/e_cgrf.html
2.Http://www.ngdc.noaa.gov/cgi-
bin/seg/gmag/fldsnth1.pl
The Magnetic North Pole is slightly different from the
True North Pole.
The WeatherMaster, like most magnetic compass,
points to the Magnetic North Pole. On the contrary,
everything measured on a map is related to the True
North Pole.
For a serious compass user who intends to perform an
accurate navigation, the compass must be adjusted for
magnetic declination.
Calibrating the compass - Magnetic Declination Mode"
Check your position by Backward Bearing Directions
! Spot two distant identifiable landmarks like mountains,
light-house, fort or building from your current position,
for example the mountains A and B.
! Check out the backward bearing directions of
mountains A and B from your current position, for
example 135 from mountain A and 270 from
mountain B.
! Use a ruler to draw a line 135 from the north at the
mountain A to your current position on the map. Draw
another line 270 from the north at the mountain B to
your current position on the map.
! Your current position on the map will be the
intersection (point A) of the lines 135 from the
mountain A and 270
! Check the Trek Course Correctly
! During a trekking, the Watch can keep your course in
a correct way. For example, the correct trail starts
from point A and finishes at point E as drawn on the
adjacent map.
! Mark the points (identifiable landmarks) where the trail
turns its direction or the trail branches its way, such
as the points A, B, C, D and E on the adjacent map.
! Find out the bearing directions of point B from point A
(315 ), point C from point B (0 ), point D from point C
(225 ), and then point E from point D (315 ).
! During the trekking, make sure that the heading
direction is 315° from point A to point B. Performing
the similar checking in other sections of the trail
helps you keep your course correctly.
IMPORTANT: If you are in doubt of the directions and
positions of the trail, consult the park administration office
before starting the trekking.
°
°
°
°
°
° from the mountain B.
°
°
°
°
Magnetic Declination Compensation
! To compensate for an object's bearing, either
subtract westerly (W) magnetic declination or add
e a s t e r l y ( E ) m a g n e t i c d e c l i n a t i o n w i t h t h e
magnetic bearing.
°
°
°
°
°
°
°
°
! Example 1: Westerly magnetic declination
23°and the compass needle points 323°.
! TB = MB - W. When MB = 323 ; W =23
! TB = 323 - 23
! TB = 300°
! The true bearing is 300°.
! Example 2: Easterly magnetic declination 22°
and the compass needle points 278°.
! TB = MB + E. When MB = 278 ; E = 22
! TB = 278 + 22
! TB = 300°
! The true bearing is 300°.
! The Watch allows you to compensate the
compass bearing at a place where the magnetic
declination is either Westerly declination or
Easterly declination.
! Check the coming section "Calibrating the
Compass" for more details of the setting.
True North
Magnetic
Declination
Magnetic
Declination
Magnetic
North
4110 m
2120 m
3120 m
point A
(starting point)
point B
A Sample Trail on a Map
point D
point E
(finish point)
point C
315°
225°
0°
315°
mountain B
Check Current Position By Backward Bearing
mountain A
270°
135°
point A
0
0
Compensate th e Bearin g
with Weste rly (W ) Magnetic Declin atio n
Compensate th e Bearin g
with Easte rly (E ) Magnetic Declin atio n
Tru e Bearin g (T B) =
Magneti c Bearin g (M B) - Weste rly Magneti c Decli nati on (W )
Tru e Bearin g (T B) =
Magneti c Bearin g (M B) + Easte rly Magneti c Decli nati on (E )
300° (T B) = 278° (M B) + 22° (E )
300°
=
(M B) - 23 (W )
(T B)
323°
°
magnetic
declination
23° W
magnetic
declination
22° E
true
bearing
300°
true
bearing
300°
magnetic
bearing
323°
magnetic
bearing
278°
true north
0°
true north
0°
magnetic
north
magnetic
north
object B
object B
point A
point A
No. Country/Place
Major City Declination
1
Afghanistan
Kabul
+3E
2
Australia
Canberra
+12E
3
Austria
Vienna
+3E
4
Bahrain
Manama
+2E
5
Bangladesh
Dhaka
+0E
6
Belgium
Brussels
+0E
7
Brazil
Brasilia
-21W
8
Canada
Ottawa
-14W
9
Chile
Santiago
+3E
10 China
Beijing
-6W
11 China
Hong Kong
-2W
12 Costa Rica
San Jose
-1W
13 Cuba
Havana
-4W
14 Czech Republic
Prague
+3E
15 Denmark
Copenhagen
+3E
16 Egypt
Cairo
+4E
17 Finland
Helsinki
+8E
18 France
Paris
-1W
19 Germany
Berlin
+3E
20 Greece
Athens
+4E
21 Hungary
Budapest
+4E
22 India
New Delhi
+1E
23 Indonesia
Jakarta
+1E
24 Israel
Jerusalem
+4E
25 Italy
Rome
+2E
26 Japan
Tokyo
-7W
27 Jordan
Amman
+4E
28 Kenya
Nairobi
+0E
29 Korea
Seoul
-8W
30 Malaysia
Kuala Lumpur
+0E
31 Mexico
Mexico City
+6E
32 Nepal
Kathmandu
+0E
No. Country/Place
Major City Declination
33 Netherlands
Amsterdam
+0E
34 New Zealand
Wellington
+22E
35 Norway
Oslo
+2E
36 Pakistan
Islamabad
+2E
37 Philippines
Manila
-1W
38 Portugal
Lisbon
-3W
39 Russia
Moscow
+10E
40 Singapore
Singapore
+0E
41 South Africa
Cape Town
-24W
42 Spain
Madrid
-2W
43 Sweden
Stockholm
+5E
44 Switzerland
Bern
+1E
45 Taiwan
Tai-pei
-4W
46 Thailand
Bangkok
-1W
47 UAE
Abu Dhabi
+2E
48 United Kingdom
London
-2W
49 United States
Washington, DC
-11W
50 United States
Juneau
+22E
51 United States
Phoenix
+11E
52 United States
Little Rock
+1E
53 United States
Sacramento
+14E
54 United States
Denver
+9E
55 United States
Atlanta
-4W
56 United States
Honolulu
+10E
57 United States
Boston
-15W
58 United States
Saint Paul
+1E
59 United States
Jackson
+0E
60 United States
Santa Fe
+9E
61 United States
Oklahoma City
+5E
62 United States
Salem
+16E
63 United States
Harrisburg
-11W
64 United States
Salt Lake City
+12E
NOTE: Since magnetic declinations will be changed with time, it is recommended to check the updated data from following sites:
http://www.magnetic-declination.com/ & http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp