Frequently Asked Questions
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1.
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What is a clinometer?
A clinometer is an instrument that measures the angular distance in degrees from the horizon (0°) to an object below or above the horizon. The Suunto clinometer looks similar to the compass and is needed for accurate measurements of an objects height above the horizon.
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How does a compass work?
We refer you to Marshall Brain's HowStuffWorks web site for a description on how a compass works.
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Why are there Magnetic Compass Zones?
The horizontal and vertical components of the earth's magnetic field vary considerably at different locations on the Earth. To get an accurate reading from a compass, the compass needle needs to be "balanced", so it does not drag on the top or bottom of the compass capsule. Because of the variations of the earth's magnetic field, a compass needle that "balances" perfectly in North America will drag or stick in South America. To accommodate these magnetic variances, the compass industry has divided the earth into 5 "zones".
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4.
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What is Magnetic Inclination or "Dip"?
The Earth's magnetic field causes a compass needle to tilt or dip. To counter the effect of Magnetic Inclination, compasses are balanced to work in specific regions or zones. (see FAQ)
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5.
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What is a "Global" compass?
Suunto has developed a patented Global Needle that will perform perfectly with needle tilts of up to 20 degrees. The compass needle and magnet are separated in the Suunto Global Navigator allowing it to be used effectively in all 5 of the earth's zones.
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6.
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What is Magnetic Declination?
Magnetic declination is sometimes referred to as the magnetic variation or the magnetic compass correction. It is the angle formed between true north and
magnetic north. Declination varies from 0 to 30 degrees in most populated regions of the world. These declination values usually change slightly over time, as the earths plates shift. By convention, declination is measured positive east and negative west (i.e. declination of -6 means 6 degrees west of north). A magnetic declination of 12 degrees West means that magnetic North lies 12 degrees West of true North. sunPATH can make Sun calculations taking into account the Magnetic Declination of a location, allowing you to use your compass without any corrections.
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How can I determine the Magnetic Declination?
Three different methods to determine a locations Magnetic Declination:
• National Geophysical Data Center Web Site
Click here to go to their site to calculate the Magnetic Declination. You will need to enter the locations Latitude and Longitude. You do not need to know the altitude, it is usually negligible for our purposes (sun positioning). The results page will display an array of data. The declination value is the first one listed under the letter "D".
Negative values are for a western declination (i.e. D of -6 means 6 degrees west of north). The yearly change is under the label "dD". The value is in minutes per year. Remember 60 minutes to a degree. The declination would need to change 60 minutes a year to change 1 degree. This change is usually negligible for our purposes. The change is more pronounced near the poles.
• US Geological Survey Maps
Click here to view a world map of the Magnetic Declination.
• Direct measurement with a map and compass
When your position is known, take a magnetic bearing to a landmark that is both visible on the terrain and represented on the map. Distinct and distant landmarks, such as a sharp mountain peak, a transmission tower, one edge of a lake or a river bend can be used. Next, measure the true bearing on the map using your compass as a protractor. The difference is simply the declination. To increase confidence, take bearings on different landmarks and average the declination results.
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What are compass deviations?
Compass deviation is a false reading from the compass due to outside forces. Steel and Iron objects as well as electric circuits close to the compass may cause deviation. Large structures like buildings will cause deviation at some distance. When using the compass, keep it well clear of metallic objects (knifes, wristwatches, light meters, lighters, steel rimmed eyeglasses and belt buckles); they can cause serious errors.
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How do I use the Suunto Optical sighting instruments?
Click here to see an example on using the Suunto Optical Sighting compass and clinometer.
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10.
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Where do I find warranty service or repairs for my Suunto instruments?
Suunto USA
2151 LAS PALMAS DRIVE, STE F
CARLSBAD, CA 92009-1525
(800) 776-7770 or (760) 931-6788
Fax: (760) 931-9875
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