First of all thanks for the article. Recently I have encountered some problems with my compass. I was in forest when noticed that it stopped to work correctly and also something like a bubble of air appeared in the compartment when the needle is attached. The bubble disappeared when I returned home and the compass again was working fine. I thought that maybe it had something to do with temperature outdoor but it wasn't really low maybe slightly below freezing. Can someone offer any explanation?
A small bubble at low elevation can and often does become much larger at higher elevations. Typically it is not a problem but if you noticed it made the compass inaccurate you may need to replace it. Check out the warranty on the compass, Sylvia for example should replace it for free. Good luck.
Hello vanman798,
i'm walking in the hill/mountains for some years now but only this year i start exploring the orientation side and a completly new world has opened in front of my eyes! I have read many articles on orientation but yours is far the best, most thorough and clearly written! thank you very much for your effort.
I have few questions created by the article and i would appreciate if you could enlight me..
At the Bearings section:
1) 2nd paragraph, last line: ''travel arrow pointing your way'' should that be pointing towards your destination?
2) 3rd paragraph : why 120 degrees? can it be any other degree?
At the Declination section:
1)3rd paragraph: declination is changing by 0° 7' W means that we have Westerly Declination?
2) In the 1960 map, the declination is 15 degrees East, so in order to find the 2007 value we subtract (15 - 5.5). If it was 15 degrees West, should we have add (15+5.5)?
3) on the same subject: if, say, we had to subtract 17 degrees (15-17), what we would have then?
Extra questions:
1)Have you written any article on explaining maps?i would like to read it!
2)Have you written any article about inclination?
3)What's going on with the ADD/SUBTRACT rules when we are at the South Hemisphere?
Hello Panas, See your questions and my answers below:
1) 2nd paragraph, last line: ''travel arrow pointing your way'' should that be pointing towards your destination?
Yes
2) 3rd paragraph : why 120 degrees? can it be any other degree?
You make 3 turns of 120 degrees and 3 * 120 = 360 (a circle), hence you are back where you started.
At the Declination section:
1)3rd paragraph: declination is changing by 0° 7' W means that we have Westerly Declination?
Declination is approaching zero. So if it is changing 0° 7' W it is making an easterly declination that much closer to zero. Easterly declinations change by a west amount, and westerly declinations change by an east amount.
2) In the 1960 map, the declination is 15 degrees East, so in order to find the 2007 value we subtract (15 - 5.5). If it was 15 degrees West, should we have add (15+5.5)?
No, remember easterly declinations are changing by a west amount, and westerly declinations are changing by an east amount. So you always subtract the amount of change from the original value regardless of east or west.
3) on the same subject: if, say, we had to subtract 17 degrees (15-17), what we would have then?
The amount of change (17 in this example) can never exceed the original value (15 in this example). So this scenario is impossible.
Extra questions:
1)Have you written any article on explaining maps?i would like to read it!
Sorry I haven't.
2)Have you written any article about inclination?
Sorry, but no.
3)What's going on with the ADD/SUBTRACT rules when we are at the South Hemisphere?
They don't change. Compass dip is what changes from one hemisphere to the next.
Thanks for your effort for anwering my questions vanman798. I'm trying to understand navigation by theory and practice. I understand the answers although i need more practice in order to comprehend them. i'm patient! :)
may i ask another question?
In your article you are stating Easterly or Westerly declination according to where you are in relation to agonic line (where True North is equal to Magnetic North) and that we need to take into account the declination in order to navigate with a map.
In my research, i found that Easterly or Westerly declination has to do with where you are in relation to True north and that there is also the Easterly or Westerly grid magnetic angle(where you are in relation to grid north)which is more important for map navigation.
At every map there are three angles to be stated. Grid magnetic angle (angle between grid north and magnetic north), declination or magnetic declination (angle between true north and magnetic north) and convergence angle (angle between true north and grid north). And when you are using a compass/map combination to navigate, you actually need to adjust the grid magnetic declination rather the magnetic declination.
Is that true according your knowledge? and if yes, then which is the importance (if any)on knowing the magnetic declination in compass/map navigation?
panamos - Aug 18, 2009 6:21 am - Voted 10/10
Well done!Amazingly written, very enlightening!
Keep up the good work.
vanman798 - Aug 24, 2009 12:32 pm - Hasn't voted
Re: Well done!Thx
Bob Burd - May 8, 2012 11:31 pm - Voted 10/10
AwesomeYou should write a book - it's that good!
vanman798 - May 13, 2012 3:25 pm - Hasn't voted
Re: AwesomeThanks Bob. I put a lot of effort into it and I'm glad to know it shows.
tomasz - Jan 4, 2013 8:32 pm - Hasn't voted
need some explanationHi,
First of all thanks for the article. Recently I have encountered some problems with my compass. I was in forest when noticed that it stopped to work correctly and also something like a bubble of air appeared in the compartment when the needle is attached. The bubble disappeared when I returned home and the compass again was working fine. I thought that maybe it had something to do with temperature outdoor but it wasn't really low maybe slightly below freezing. Can someone offer any explanation?
vanman798 - Jan 5, 2013 7:47 pm - Hasn't voted
Re: need some explanationA small bubble at low elevation can and often does become much larger at higher elevations. Typically it is not a problem but if you noticed it made the compass inaccurate you may need to replace it. Check out the warranty on the compass, Sylvia for example should replace it for free. Good luck.
Panas - Feb 5, 2014 4:49 pm - Voted 10/10
Excellent by all means!Hello vanman798,
i'm walking in the hill/mountains for some years now but only this year i start exploring the orientation side and a completly new world has opened in front of my eyes! I have read many articles on orientation but yours is far the best, most thorough and clearly written! thank you very much for your effort.
I have few questions created by the article and i would appreciate if you could enlight me..
At the Bearings section:
1) 2nd paragraph, last line: ''travel arrow pointing your way'' should that be pointing towards your destination?
2) 3rd paragraph : why 120 degrees? can it be any other degree?
At the Declination section:
1)3rd paragraph: declination is changing by 0° 7' W means that we have Westerly Declination?
2) In the 1960 map, the declination is 15 degrees East, so in order to find the 2007 value we subtract (15 - 5.5). If it was 15 degrees West, should we have add (15+5.5)?
3) on the same subject: if, say, we had to subtract 17 degrees (15-17), what we would have then?
Extra questions:
1)Have you written any article on explaining maps?i would like to read it!
2)Have you written any article about inclination?
3)What's going on with the ADD/SUBTRACT rules when we are at the South Hemisphere?
thank you very much for your time!
vanman798 - Feb 8, 2014 10:53 pm - Hasn't voted
Re: Excellent by all means!Hello Panas, See your questions and my answers below:
1) 2nd paragraph, last line: ''travel arrow pointing your way'' should that be pointing towards your destination?
Yes
2) 3rd paragraph : why 120 degrees? can it be any other degree?
You make 3 turns of 120 degrees and 3 * 120 = 360 (a circle), hence you are back where you started.
At the Declination section:
1)3rd paragraph: declination is changing by 0° 7' W means that we have Westerly Declination?
Declination is approaching zero. So if it is changing 0° 7' W it is making an easterly declination that much closer to zero. Easterly declinations change by a west amount, and westerly declinations change by an east amount.
2) In the 1960 map, the declination is 15 degrees East, so in order to find the 2007 value we subtract (15 - 5.5). If it was 15 degrees West, should we have add (15+5.5)?
No, remember easterly declinations are changing by a west amount, and westerly declinations are changing by an east amount. So you always subtract the amount of change from the original value regardless of east or west.
3) on the same subject: if, say, we had to subtract 17 degrees (15-17), what we would have then?
The amount of change (17 in this example) can never exceed the original value (15 in this example). So this scenario is impossible.
Extra questions:
1)Have you written any article on explaining maps?i would like to read it!
Sorry I haven't.
2)Have you written any article about inclination?
Sorry, but no.
3)What's going on with the ADD/SUBTRACT rules when we are at the South Hemisphere?
They don't change. Compass dip is what changes from one hemisphere to the next.
Hope this clears up your questions. Thanks
Panas - Feb 9, 2014 11:03 am - Voted 10/10
One more..Thanks for your effort for anwering my questions vanman798. I'm trying to understand navigation by theory and practice. I understand the answers although i need more practice in order to comprehend them. i'm patient! :)
may i ask another question?
In your article you are stating Easterly or Westerly declination according to where you are in relation to agonic line (where True North is equal to Magnetic North) and that we need to take into account the declination in order to navigate with a map.
In my research, i found that Easterly or Westerly declination has to do with where you are in relation to True north and that there is also the Easterly or Westerly grid magnetic angle(where you are in relation to grid north)which is more important for map navigation.
At every map there are three angles to be stated. Grid magnetic angle (angle between grid north and magnetic north), declination or magnetic declination (angle between true north and magnetic north) and convergence angle (angle between true north and grid north). And when you are using a compass/map combination to navigate, you actually need to adjust the grid magnetic declination rather the magnetic declination.
Is that true according your knowledge? and if yes, then which is the importance (if any)on knowing the magnetic declination in compass/map navigation?
thanx again
Buck Owens - Feb 13, 2018 10:19 am - Hasn't voted
TN surrendered to KY ?I enjoyed this article very much. Very helpful. The black and white declination map has me puzzled though.