What Is a Compass?
Parts of a Compass
There are many types of compasses ranging from tiny thumb compasses to complex high-tech gadgets. For most hikers and outdoors guys like us, an orienteering compass works just great and that is what we'll discuss here.
Not all compasses include each of these parts and some compasses include even more. | |
Baseplate | hard, flat surface on which the rest of the compass is mounted. It has a rulers on its edges for measuring distances on maps. It's edge is straight and useful for laying lines on a map |
Scales | each edge of a compass may have different rulers for use with different map scales |
Direction-of-Travel Arrow | marked on the base plate. You point this the way you will be traveling |
Magnifier | for seeing small map features better |
Index Pointer | butt end of the direction-of-travel arrow. It ends right at the edge of the dial and is where you take degree readings |
Dial | ring around the housing that has degree markings engraved. You hold the dial and rotate it to rotate the entire housing |
Declination Marks | use to orient the compass in an area with known declination |
Orienting Arrow | marked on the floor of the housing. It rotates with the housing when the dial is turned. You use it to orient a compass to a map |
Orienting Lines | series of parallel lines marked on the floor of the housing and on the base plate |
Needle | magnetized piece of metal that has one end painted red to indicate North. It sits on a fine point that is nearly frictionless so it rotates freely when the compass is held fairly level and steady |
Housing | main part of the compass. It is a round plastic container filled with liquid and has the compass needle inside |
Bubble | a bubble of air in the housing liquid is useful for making sure you are holding the compass fairly level |
Mirror | lets you see the compass face and distant objects at the same time. Useful for emergency signaling |
Sight | improves aiming your compass at distant objects |
How a Compass Works
There is a huge magnetic field around the earth. It is huge, but it is not very strong. The magnetized needle in a compass is aligned with this magnetic field. As the image below shows, the composition of the earth acts as a huge bar magnet sitting upside down in the middle of the planet. Since its South end is at the north pole and its North end is at the south pole, the North end of a compass needle is pulled north.
Your compass has to have a very light needle sitting on a pivot that has almost no friction. This is because the earth's magnetic field is weak and would not be able to turn the needle. You can even make your own compass just for fun.
Next: Reading a Compass
The Tate's Compass company manufactured over 1 million compasses a year. But, one day the red and white paint got mixed up so all their compasses pointed the wrong way. The company went out of business and the well-known saying was created: |
Search Google News for more 'Lost Hiker' news items. |
09 Oct 2024 - 45 Rescuers and Two K9 Units Search For Missing Hiker In New York |
07 Oct 2024 - Lost Youth Hiker Located in Webster |
07 Oct 2024 - Lost hiker found on Bachelor Brook trailhead in Granby |
04 Oct 2024 - Search Mission for Missing Yellowstone Hiker Turns Desperate |
05 Oct 2024 - HFD rescues lost hiker on Aiea Loop Trail after 4 |
18 Jul 2024 - A Hiker Was Lost in the Santa Cruz Mountains for 10 Days; I Retraced His Steps to Find Out Why |
Comments:
Nov 16, 2015 - Sabrina
I love to learn about compasses
Apr 12, 2016 - Gaurav VermaIs it possible to get this guide as a pdf?
Apr 12, 2016 - Compass Dude@Gaurav - No, this website is not available as a PDF file.
Jul 27, 2016 - alex macdonaldyour website is awesome I learnt so much
Sep 22, 2016 - Bill ToneyIs the declination arrow and the orienting arrow the same thing?
Sep 22, 2016 - Compass Dude@Bill - Yes, you can adjust the orienting arrow for declination.
See Declination page.
May 25, 2017 - ignacio pouThis website is awesome.
I have learn a lot about compasses.
A thousands of thanks.
Sep 08, 2017 - Ralph G. SwansonI have learn a lot about compasses.
A thousands of thanks.
Did I understand correctly? South of the equator, the red painted
end of a compass needle points to the South Pole? If so are Scouts
in Australia taught to orient everything and read maps based on
everything pointing south?
Sep 17, 2017 - Compass Dude@Ralph - No, the red end always points to magnetic north, wherever
you are.
Jan 29, 2018 - shin ri kimi really understand now the part of compass and i know how to use it
Mar 17, 2020 - FestusHello, thanks for the page. I have a question please: Must the 360 dial and the orienting arrow be at the index pointer as in the picture above before any measurements with the compass?
Mar 19, 2020 - Compass Dude@Festus - No, the dial turns the housing which includes the
orienting arrow depending on declination. Then, bearings are taken
by putting "red in the shed".
You might read the Orienting Map and Compass Use pages.
Jun 29, 2021 - the other compass dudeYou might read the Orienting Map and Compass Use pages.
Hey Dude,
Do you know anyone who can get a 1917 Verner's pattern Mark VIII compass card that is in good condition? Mother of pearl would be wonderful but aluminum will work also. I have fully restored the Mark 8 except for the ratty old card, well it is 104 years old but it looks ratty next to brass so shiny you can see your face in. Any help would really be appreciated.
Thanks.
Jul 06, 2024 - StephenDo you know anyone who can get a 1917 Verner's pattern Mark VIII compass card that is in good condition? Mother of pearl would be wonderful but aluminum will work also. I have fully restored the Mark 8 except for the ratty old card, well it is 104 years old but it looks ratty next to brass so shiny you can see your face in. Any help would really be appreciated.
Thanks.
The tic marks on my Silva Explorer, and on the compass you
show in the picture are not evenly spaced (on the 1:24k
scale.). Why is that?
Jul 07, 2024 - Compass Dude@Stephen - The tick marks are for 1/10th mile increments and are
all evenly spaced. Extra ticks are shown for 1/4 and 3/4 mile
which fall halfway between two 1/10th mile tick marks.
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