Magnetic declination is an essential principle to understand when navigating your way through the wilds with map and compass.
Yet it's a tricky thing to remember, at least the way it has traditionally been taught, using an addition / subtraction method. Just when you think you've grasped it, the concept floats away, like fog in the morning light.
Well there is a simple, practical approach to adjusting for magnetic declination when finding your bearings. The whole explanation begins with a definition of 'north."
There are 2 Norths
A lot of people know that there are 2 norths in terms of maps and compasses. A map shows true north, or the Geographic North Pole where all lines of longitude meet. The earth rotates around an imaginary axis that runs through the North and South Poles.
A compass needle points to magnetic north, which is determined by the earth's magnetic field. The location of magnetic north moves over time, at about 5 miles per hour. Right now it is slowly creeping around somewhere NW of Hudson's Bay in Canada, about 450 miles away from true north.
Magnetic Declination
The angular difference between true north and magnetic north is known as "declination," or "variation" in the aviation world. Declination is different for different parts of the globe. In Washington State, the angle of declination is 20?east. This means that magnetic north is 20? east of true north. In Tennessee the angle of declination is 0?, and in Maine, it's 20? west.
Declination values can be found in the margins or legend on topographic maps. Because the point of magnetic north is constantly moving, it is important to have a recent topo map for finding your way in the woods.
A similar point to remember is that compasses are calibrated for different parts of the world. So when you purchase a compass, be sure that it is intended to be used in the area of your big hiking vacations.
How to Find Your Bearing
Follow these steps to find your bearing:
1. Place the compass on the map with the arrow on the base plate pointing in the direction you want to go.
2. Turn the dial face of the compass so that north on the compass is parallel with north on the map.
3. Place your compass level in the palm of your hand and turn yourself until the needle in the compass aligns with the North marking on the face dial.
4. The big arrow on the base plate is now aligned with your bearing.
Declination Value and Bearings - A Trick to Make it Stick
If you walked 10 miles through the woods in Washington State, without factoring declination value in your bearings, you would finish over 3 miles off target. That's too much!
To avoid confusion in finding bearings, keep the central principle in mind:
Make map bearing = magnetic bearing.
You will achieve this in the field by adjusting your bearings to compensate for magnetic declination. There are 2 ways to account for magnetic declination in finding your bearings: an adjustable compass and marking your non-adjustable compass.
The easiest way is with an adjustable compass. Simply turn the declination adjustment screw on the compass to the correct value and all readings are automatically converted to true north. If it's available, it's always best to have an adjustable compass on your walk.
The next best way to account for declination is to mark the declination value on your non-adjustable compass at the beginning of your journey.
That's simple to do. For example, when the map indicates a declination value of 20? west, you will mark your compass dial at 340?. If the map indicates a declination value of 10? east, you will mark your compass at 10?. Make the mark with a permanent marker and erase later with rubbing alcohol.
Now when you take your bearings in the field, place your compass level in the palm of your hand and turn yourself until the needle in the compass aligns with the declination marking on the face dial. Then the big arrow on the base plate will point toward your bearing and automatically compensate for magnetic declination.
Outdoors Adventurer, Writer and Webmaster Will Robertson lives with his family in Little Rock, Arkansas.
Explore the best hiking vacations and gear on the planet at: http://www.hiking-vacations-and-gear.com
Chicago charter limousine Crystal Lake .. Lockport Chicago limo O’HareThousands of golfers flock to the Carolinas each spring and... Read More
The last thing you want on an African safari is... Read More
Isn't it time you stepped out of the concrete jungle... Read More
Most people, who go on a family beach vacation, take... Read More
River rafting is a major attraction in California. The most... Read More
Spain offers the visitor over 4,000 kms of coastline where... Read More
There were four of us on that first Tom Sawyer... Read More
Mystic Seaport celebrates the seafaring past of New England. Known... Read More
Oregon's Rogue River is one of the nation's most beautiful.... Read More
How to get discount lift tickets for popular ski resorts... Read More
Contrary to what many think, ultralight backpacking is not just... Read More
Solo backpacking means peace and quiet. No one to talk... Read More
Have you ever had a backpacking trip that was a... Read More
Back from our family's vacation to Costa Rica, I am... Read More
The kind of things you pack when you go on... Read More
Camping for fun is a great way to enjoy the... Read More
You would think that a cheap safari in Africa for... Read More
For the fortunate few, life isn't complete without a backpacking... Read More
Romancing History ? A Holiday in RajasthanRajasthan, the name evokes... Read More
A Hawaii volcano tour can be a most memorable experience,... Read More
Have you ever thought you might like to try a... Read More
For some 30 years I practiced law in Mesa, Arizona.... Read More
If anyplace on earth is a natural paradise, Plitvice Lakes... Read More
Boston is a great destination city for a vacation. There's... Read More
The dictionary defines a tent as 'a portable shelter usually... Read More
Lincolnshire car service to O'Hare ..It is the downhill ski racing competition of the winter... Read More
Plimoth Plantation and the Mayflower II ship are major attractions... Read More
Malaria is endemic to most of the areas in Africa... Read More
Are walking sticks longer than trekking poles? What about hiking... Read More
Camping is an excellent way to explore and experience the... Read More
Generally speaking, Greek drivers are not the best in Europe,... Read More
How to get the most out of your trekking poles... Read More
Spain: sun, sea, sand and Spanish... discover us! Spain, a... Read More
A Hawaii volcano tour can be a most memorable experience,... Read More
Normally when you think Safari you think Big 5. The... Read More
Have you ever thought you might like to try a... Read More
Packing in general can be a hassle. But when going... Read More
The kind of things you pack when you go on... Read More
Zambia is Africa's best kept secret as far as safaris... Read More
The owner can attempt small inflatable boat repair if factory-gluing... Read More
Scotland has taken its place as the new Mecca for... Read More
Romancing History ? A Holiday in RajasthanRajasthan, the name evokes... Read More
Most people, who go on a family beach vacation, take... Read More
The Cairns Fishing Adventure A Great Australia Road TripYou love... Read More
Why should you use hiking poles is perhaps the first... Read More
Western Australia Driving Adventure Great Australian Road Trip Large... Read More
A rigid inflatable boat is defined as a hard-hulled boat... Read More
Magnetic declination is an essential principle to understand when navigating... Read More
Stay warm or die. That's what it comes down to... Read More
When you search online for a camping gear outlet you... Read More
Outdoors |