Author Topic: Numbering systems on the outside of a compass bezel  (Read 1553 times)

Rob Goes Walking

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Oh dear I think I've made a mistake buying my compass. I expected the numbers to run 0 to 359 on the bezel but they don't, the run to 63.5 with the cardinals replacing some numbers. The compass I bought is a Silva Compass 4 Militaire on account of recognising the brand name, it being cheap for the brand, having all the map scales on it and saying it was luminous. What have I bought? Why is it numbered funny? Any suggestions on a replacement compass or how to use this one? While I suppose it would sort of work if all the bearings used the same system adjusting for magnetic declination would be tricky.

Mel

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Re: Numbering systems on the outside of a compass bezel
« Reply #1 on: 16:47:17, 25/04/19 »
I just googled it.  The red and black numbers inside the twizzly bit look as if they're the numbers you need.
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ninthace

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Re: Numbering systems on the outside of a compass bezel
« Reply #2 on: 16:49:36, 25/04/19 »
The clue is in the word militaire.  You have bought a military compass.  The army, god bless 'em use things called 'mils instead of degrees, makes it easier for the artillery to miss things. There are 6400 mils in a circle, if you want to know more, Google is your friend.  In the meantime, if you go into Kirkby Stephen tomorrow, there are, or were, two outdoors shops.  one near the market square on the left as you go towards Brough and the other on the left as you go the opposite way from the market square where you can get a proper compass. Best place to park by the way is the car park up towards the grammar school opposite the medical centre.  There is an alley from there past the cattle market to the square.
Solvitur Ambulando

Rob Goes Walking

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Re: Numbering systems on the outside of a compass bezel
« Reply #3 on: 16:58:16, 25/04/19 »
Thank you Mel and ninthace. The numbers inside the bezel are too hard to read off the index so close together, especially so close to the orienteering arrow for magnetic declination. I'll get another compass. Another lesson learned.

Pitboot

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Re: Numbering systems on the outside of a compass bezel
« Reply #4 on: 17:00:07, 25/04/19 »
Using a compass with mils is just the same as using a compass with degrees, except the units are different.
North is still north and south is still south.
I learned to navigate at age 16 with degrees, joined the army, no difficulty using mils there, and as a civvy use degrees again, can't see the problem.
 It's sort of like using MPH and then having to think KPH when you drive overseas.
I still have a Silva compass from my army days marked in mils, it gets used a lot, and so does my newer degree marked compass. The only reason I sometimes use the newer one is that it has a 1:40000 scale on the base plate and I use Harvey maps.
If I should fall to rise no more,
As many comrades did before,
Then ask the fifes and drums to play.
Over the hills and far away.

ninthace

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Re: Numbering systems on the outside of a compass bezel
« Reply #5 on: 17:04:32, 25/04/19 »
Shops in Kirkby Stephen are Mad About Mountains and Eden Outdoors


Solvitur Ambulando

Rob Goes Walking

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Re: Numbering systems on the outside of a compass bezel
« Reply #6 on: 17:10:11, 25/04/19 »
Pitboot, part of the reason I bought this one is it has a 1:40000 scale on the baseplate (as well as 1:25000 and 1:50000). I could use it and use a calculator to get degrees in mils for magnetic declination. I'd rather have a civvy measuring system one though I'm not the military!

Thanks for the shop info ninthace.

ninthace

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Re: Numbering systems on the outside of a compass bezel
« Reply #7 on: 17:23:09, 25/04/19 »
Small military joke.  There are two Corps in the Army with the same motto - Ubique.  The Royal Engineers and the Royal Artillery (see this creeping back to a mils reference?).  For the Royal Engineers Ubique means "Everywhere" to signify that they have been present at all the Army's major battles.  For the Royal Artillery it also means "Everywhere" or perhaps more precisely "All Over the Place".
Solvitur Ambulando

Rob Goes Walking

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Re: Numbering systems on the outside of a compass bezel
« Reply #8 on: 17:27:53, 25/04/19 »
Very good. On the subject of jokes and engineers:

A man is flying in a hot air balloon and realizes he is lost. He spots a man down below and lowers the balloon to shout: “Excuse me, can you help me? I promised my friend I would meet him half an hour ago, but I don’t know where I am.”

The man below says: “Yes. You are in a hot air balloon, hovering approximately 30 feet above this field. You are between 40 and 42 degrees N. latitude, and between 58 and 60 degrees W. longitude.”

“You must be an engineer” says the balloonist.

“I am” replies the man. “How did you know.”

“Well” says the balloonist, “everything you have told me is technically correct, but I have no idea what to make of your information, and the fact is I am still lost.”

The man below says “You must be a manager.”

“I am” replies the balloonist, “but how did you know?”

“Well”, says the man, “you don’t know where you are, or where you are going. You have made a promise which you have no idea how to keep, and you expect me to solve your problems. The fact is you are in the exact same position you were in before we met, but now it is somehow my fault.”

alan de enfield

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Re: Numbering systems on the outside of a compass bezel
« Reply #9 on: 17:37:40, 25/04/19 »
Many years ago I was teaching orienteering at an International Scout camp.

I had one team which seemed to have a consistent problem in heading off at the correct heading, called them back, off they went again in the wrong direction, called them back ………….. same again.

They were a group from Norway, and on closer examination their compass was a 'metric' compass that has 400 degrees and a right angle (ie due East) was 100 degrees.

I subsequently found out that in fact it was a 'Gradian' compass with 400 grads to a circle / 100 to a right angle.

As an aside...  NATO military compasses use 'mils' which range from 0-6400. The 'Mils' system is based on Radians. There are 2π Radians in a circle. So technically there are 6283 mils in a circle, but this gets modified to 6400 for convenience except for the Swedish armed forces which round it to a more exact, but slightly more annoying 6300 and former Warsaw Pact countries which round down to an anticlockwise 6000 mils - so beware of buying old Soviet-era compasses.

Surveyors and other militaries may use gradians. They are the metric form of Degrees - there are 400 Gradians in a circle.

The mils system has the useful property that 1 mil subtends 1 meter at 1 kilometer. Useful when calling in direct (machine guns) or indirect (mortar, artillery) fire.

Hey, some fellow hikers can be annoying. You just never know when this information can be useful… For civilian uses, degrees are the norm.

Rob Goes Walking

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Re: Numbering systems on the outside of a compass bezel
« Reply #10 on: 17:50:33, 25/04/19 »
Interesting and educational post Alan,  ;D at calling in fire on other hikers. Apart from the ones who hog the summit when others are around (I think they're known as summit slugs around this forum) I've yet to be annoyed be another hiker. I'll give it time.

Pitboot

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Re: Numbering systems on the outside of a compass bezel
« Reply #11 on: 20:05:46, 25/04/19 »
My experience of the "dropshorts" when training in Canada was that despite sending them an eight figure grid reference and accurate adjustments in 100 mil increments they still managed to lob their 105mm bullets somewhere between me and my HQ troop.
If I should fall to rise no more,
As many comrades did before,
Then ask the fifes and drums to play.
Over the hills and far away.

archaeoroutes

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Re: Numbering systems on the outside of a compass bezel
« Reply #12 on: 21:22:50, 25/04/19 »
There is actually no need for the numbers in most navigation. You set the compass from the map and then walk on it - no need for numbers.
Of course, when there's a significant variation, there'll be a need to correct for it, but even then only the divisions matter, not the actual numerical bearing.
Walking routes visiting ancient sites in Britain's uplands: http://www.archaeoroutes.co.uk

Rob Goes Walking

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Re: Numbering systems on the outside of a compass bezel
« Reply #13 on: 21:32:12, 25/04/19 »
There is actually no need for the numbers in most navigation. You set the compass from the map and then walk on it - no need for numbers.

Good to know. The only ones in the book which the numbers mattered for (apart from adjusting for magnetic declination) I think were running bearings and double bearing in the advanced section and only then as limits you could calculate in mils. I do realise I'm being a bit precious sending my Militaire back and getting one in degrees but I'll enjoy it more if I'm pleased with the kit.

Mel

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Re: Numbering systems on the outside of a compass bezel
« Reply #14 on: 22:03:11, 25/04/19 »
.... No need to worry about magnetic declination either in this country.
No expense spared in pursuit of a bargain ;)
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