Does a compass work at the equator?

[grungeboater]

This was probably covered in high schoold science class but that was yesteryear. So if I may pose the question to someone in the know....I will be traveling to ecuador soon and wonder if a compass is useful in the equatorial regions. Isnt there a magnetic pull from both north and south poles to the extent that a compass is not useful there? Thanks

[jeffro]

The north end of a compass points to the magnetic north pole. South End points to the magnetic south pole. This holds true wherever the hell on this globe you are.

[jeffro]

I should have also mentioned--
Compasses in the southern hemisphere are balanced diffrently. This is to make one end on the compass needle heavier than the other to account for the magnetic field pulling one of the needle down.

[DanOrion]

Northern hemisphere compasses have their magnet set at an angle down toward the north to line up nearly parallel with the earth's magnetic field. The magnet in a compass isn't the acutal needle, but rather a 2 or 3 mm magnet. There are some compasses that have the magnet set on a pin so that they work in the northern or southern hemisphere. I had a "global" Suunto once that was set on a saphire pin and worked well for high-accuracy geologic mapping in both Colorado as well as New Zealand (+/- 2 degrees). It cost about $70 in 2000. I can't find it on the Suunto website, nor an equivalent on the Silva website. In any case, I bet a northern hemisphere compass will be OK at the equator because the magnet will be close enough to parellel with the earth's field. Good luck, safe travels.

[grungeboater]

Thanks. Still not sure where this leaves me. I have a $5 Silva compass that I have always relied on for hunting and hiking in the tame forests of the midwest. I will just take it with and see what happens. I intend to do more paddling than hiking so hopefully I wont get too far off the beaten trail, nor too far from the river.

[raftus]

So the north end of the needle points north no matter were you are. Unless you are on the north pole, then the needle wants to point straight down. Thus the need for weights on the needle based on how close you are to the north pole.

There are five regions for compasses based on proximity to the North pole - going from zone 1 for North America to zone 5 for Australia. The difference is tiny weights on the needle that prevent the needle from 'grounding out' and stopping moving by having the needle touch the inside of the case. But simply tilting the compass until the needle floats free will solve this. But you may not be able to hold the compass level or use if flat against a table unless you tilt the entire table until the needle is moving freely.

Here is a map of the zones with a description:
What is a Global Needle?

Here is a link to compasses with global needles:
Global Compasses

On the plus side in Ecuador the is very little magneitic declination - so true north is close magnetic north.

[grungeboater]

Now I know why some cost nearly $100 and my $5 compass works fine where I live and should work well in Ecuador. Thanks