ArizonaHikers Portal Index
HomeHome   BoardBoard   AZH GearAZH Gear  FAQFAQ  RulesRules   SearchSearch
MemberlistMembers  ArticlesArticles  CalendarCalendar  GalleryGallery  LinksLinks      RegisterRegister
ProfileProfile   Log in to check your private messages   Log inLog in
Magnetic Declination
Goto page 1, 2  Next
 
Post new topic   Reply to topic    ArizonaHikers - Community Based Hiking Discussion Board Forum Index -> Orienteering Email to a Friend
  View previous topic :: View next topic  
Author Message
plummer150





Joined: 04 Jan 2003
Posts: 542
Location: Jersey City, New Jersey

PostPosted: 12/12/2003, 2:03 pm    Post subject: Magnetic Declination Reply to topic Reply with quote

Here is probably the most information site I have seen on the web about Magnetic Declination. A lot of the info on here I didn't even know myself until I read it. Like this:
Quote:
Most people incorrectly believe that a compass needle points to the north magnetic pole. But since the Earth's field is the effect of complex convection currents in the magma, which must be described as several dipoles, each with a different intensity and orientation, the compass actually points to the sum of the effects of these dipoles at your location. In other words, it aligns itself with the magnetic lines of force. Other factors, of local and solar origin, further complicate the resulting field. It may be all right to say that a compass needle points "magnetic north" but it only roughly points to the north magnetic dip pole.


Crazy, I always thought it was magnetic north too until I read that. Silly Heres the website. http://www.geocities.com/magnetic_declination/
_________________
"IRONMAN" cometh, hiketh, destroyeth
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
CatValet
Got Gear?




Joined: 04 Jan 2003
Posts: 735
Location: Scottsdale

PostPosted: 12/12/2003, 4:55 pm    Post subject: Reply to topic Reply with quote

It's about 14 degrees east of true north hereabouts. -R
Back to top
View user's profile Send private message Send e-mail
Nighthiker





Joined: 05 Jan 2003
Posts: 1714

PostPosted: 12/13/2003, 9:33 am    Post subject: Reply to topic Reply with quote

I had been aware of this Plummer. I have 700 plus USGS topo quads. Some of my maps the magnetic declination has gone from 12 degrees east to 14 degrees east and back to 11 1/2 degrees east. If you have some USGS topo maps for several different locations across a state, check the declination on them. You may note several degree declination difference.
Back to top
View user's profile Send private message
Tom Treks
Gear Addict




Joined: 12 Jan 2003
Posts: 3347

PostPosted: 12/13/2003, 9:37 am    Post subject: Reply to topic Reply with quote

Nighthiker wrote:
I had been aware of this Plummer. I have 700 plus USGS topo quads. Some of my maps the magnetic declination has gone from 12 degrees east to 14 degrees east and back to 11 1/2 degrees east. If you have some USGS topo maps for several different locations across a state, check the declination on them. You may note several degree declination difference.


Wow. Are any of those electronic?

I've heard that most of the high-end compasses you can buy in a given location already are set for the average declination. Is this true?
Back to top
View user's profile Send private message
plummer150





Joined: 04 Jan 2003
Posts: 542
Location: Jersey City, New Jersey

PostPosted: 12/13/2003, 9:52 am    Post subject: re: Reply to topic Reply with quote

Wow, I did not realize this at all. I do have several topo maps from different years that I'll have to check that out on. I think the latest update for the State College area is 86 and before that was 74 and I have both so I'll see whats up with that. I heard the USGS is actually going to do the State College area again here soon. I'll believe when I get the new updated topo map myself. Laughing
_________________
"IRONMAN" cometh, hiketh, destroyeth
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
azhiker96





Joined: 05 Jan 2003
Posts: 1410

PostPosted: 12/16/2003, 8:46 am    Post subject: Reply to topic Reply with quote

Tom, some of the high end compasses can be set for the local declination. They can't sense it though. If you had one you'd want to learn how to adjust it and then set it with the declination from the map where you're hiking.

However, keep in mind that the magnetic pole is moving about 10 miles a year. It's also declining and will likely switch in a couple thousand years. Maybe it's time for me to invest in one of those dang GPS units everybody loves.

http://www.rense.com/general26/poles.htm
Back to top
View user's profile Send private message
Hnak





Joined: 06 Jan 2003
Posts: 1764
Location: Prescott, AZ

PostPosted: 12/16/2003, 9:19 am    Post subject: Reply to topic Reply with quote

HikerInGilbert wrote:
I've heard that most of the high-end compasses you can buy in a given location already are set for the average declination. Is this true?


As azhiker96 stated, some of the high end compasses allow the user to set the local declination manually. What you may have heard is a reference to setting up a compass to allow for magnetic dip. The lines of the earth's magnetic field are parallel to the surface near the equator, and pretty much vertical at the magnetic poles. In between (such as where we are) the lines of the field will be dipping down toward the north magnetic pole. In the southern hemisphere, the lines will dip down toward the south magnetic pole. The closer you get to the magnetic pole, the steeper the lines dip...

Some compass manufacturers allow for this, by arranging the magnets on the compass card (internal disk) so that they dip to the north for compasses sold in the northern hemisphere, and dip to the south for compasses sold in the southern hemisphere.

See:
http://www.suuntousa.com/needle.htm

Hank
Back to top
View user's profile Send private message Send e-mail Yahoo Messenger
evenstar





Joined: 03 Jan 2003
Posts: 5548
Location: SCW by way of CA

PostPosted: 12/16/2003, 9:52 am    Post subject: Reply to topic Reply with quote

My Garmin Etrex Summit can be set for magnetic north or true north and, because it always knows it location on grid, it automatically adjusts the declination.
_________________
John Richardson and Richie Rich, El Perro de Playero
http://members.tripod.com/~evenstar/index.html
http://www.arizonahikers.com
When the Man waked up he said, "What is Wild Dog doing here?" And the Woman said, "His name is not Wild Dog anymore, but the First Friend, because he will be our friend for always and always and always. Take him with you when you go hunting."
--Rudyard Kipling, from Just So Stories, 1902
Back to top
View user's profile Send private message Visit poster's website
plummer150





Joined: 04 Jan 2003
Posts: 542
Location: Jersey City, New Jersey

PostPosted: 1/2/2004, 9:26 am    Post subject: re: Reply to topic Reply with quote

Nice, that must be great to have. Wish I had one of them!
_________________
"IRONMAN" cometh, hiketh, destroyeth
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
BoyNhisDog
The dangerous place where the winds meet




Joined: 05 Jan 2003
Posts: 1375
Location: Tucson

PostPosted: 1/2/2004, 9:44 am    Post subject: Reply to topic Reply with quote

This is my sweet baby. You can set the declination without messing up the meridain lines in the capsule. It is good for all 5 magnetic zones on this planet supposedly. It did work great in the tropics of Mexico.



Good mirror sighting



I generally keep it set to 11.5 degrees east out here.
_________________
Seize from every moment its unique novelty and do not prepare your joys
- Andre Gide
Back to top
View user's profile Send private message
bzachar





Joined: 10 Feb 2003
Posts: 88
Location: Mesa, AZ

PostPosted: 1/2/2004, 9:57 am    Post subject: Reply to topic Reply with quote

evenstar wrote:
My Garmin Etrex Summit can be set for magnetic north or true north and, because it always knows it location on grid, it automatically adjusts the declination.


Just an FYI: Every GPSR I've come across has that capability.

Even a unit like the Garmin Legend ($150 after rebate) can be set to True, Magnetic, Grid or User as the North Reference.

Bill
Back to top
View user's profile Send private message Visit poster's website
azhiker96





Joined: 05 Jan 2003
Posts: 1410

PostPosted: 1/2/2004, 2:55 pm    Post subject: Reply to topic Reply with quote

I like BoyNhisdog's compass. It's much lighter than the Garmin and doesn't need batteries! Wink I may have to get one. I've been using an older style lensatic compass. It's not as easy to transfer to a map if I want or need to triagulate. Smile
Back to top
View user's profile Send private message
BoyNhisDog
The dangerous place where the winds meet




Joined: 05 Jan 2003
Posts: 1375
Location: Tucson

PostPosted: 1/2/2004, 3:54 pm    Post subject: Reply to topic Reply with quote

AZhiker this one will do both well and weighs in at 2 ounces. I find something very satisfying about navigating with magnetized steel. Would love to have a good GPS at times though. They are so good at positioning that it's sort of spooky. Still have not got one though.

Found this one at a very inexpensive price at Forestry Supply.
_________________
Seize from every moment its unique novelty and do not prepare your joys
- Andre Gide
Back to top
View user's profile Send private message
plummer150





Joined: 04 Jan 2003
Posts: 542
Location: Jersey City, New Jersey

PostPosted: 1/11/2004, 6:20 pm    Post subject: re: Reply to topic Reply with quote

Nice compass!
_________________
"IRONMAN" cometh, hiketh, destroyeth
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
JW
I'll make rain with my spaceman powers!




Joined: 20 Sep 2003
Posts: 1286

PostPosted: 1/19/2004, 8:15 pm    Post subject: magnetic reckoning Reply to topic Reply with quote

BoyNhisDog wrote:
AZhiker this one will do both well and weighs in at 2 ounces. I find something very satisfying about navigating with magnetized steel. Would love to have a good GPS at times though. Still have not got one though.
Same here. Dead reckoning with a map, stopwatch and a decent compass is a skill that we should have to back up a GPS.
_________________
What a magnificent time to LIVE! - Everett Ruess.

Since my house burned down, I now own a better view of the rising moon. - Masahide.
Back to top
View user's profile Send private message
Back to top
Display posts from previous:   
Post new topic   Reply to topic    ArizonaHikers - Community Based Hiking Discussion Board Forum Index -> Orienteering All times are GMT - 7 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum