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  #21  
Old 07-01-2012, 10:49 AM
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Shark Bait (Stu)
'ZZ9 Plural Z Alpha'

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In addition to Adam's reply, the following numbers are a rough guide to some minimum working distances to be aware of when using compasses:

Transmission High Tension Lines.....80m
Vehicles.....75m
Railway Lines.....20m
Fencing Wire.....10m
Tools, Shovels (Steel Telescope Mounts ).....3m

Every compass, no matter how well made will have an inherant error. Once this error is known, it can be allowed for.
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  #22  
Old 07-01-2012, 11:10 AM
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suma126 (Shane)
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if you have a apple iphone the compass works very well
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  #23  
Old 07-01-2012, 11:28 AM
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mithrandir (Andrew)
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Quote:
Originally Posted by suma126 View Post
if you have a apple iphone the compass works very well
... but is subject to all the same working distance requirements as any other magnetic compass. Walking N/S (line determined by plumb and shadow) in the back yard mine swings up to 10 degrees due to interference. This totally confuses trying to use Sky Safari Pro.
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  #24  
Old 08-06-2012, 08:41 PM
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Looking for an Accurate Compass

Hello,

I'm looking to buy a compass to use on a daily basis. What I need is accuracy and affordability. Right now I'm looking at the Silva Polaris. Has any tried this one before, if so, how accurate is it? I really need an accurate compass.

Any suggestions?

Thank you,

-Knowledge
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  #25  
Old 08-06-2012, 09:35 PM
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http://www.ebay.com.au/itm/Orienteen...item43a6373e3c

Brought three of these, at $2.50 a pop you cant go wrong!
They work well, so long as they are not too close to metal and must be held level (close to, it has some play) or else the needle hits.

Not the best, but gets me to true south roughly and then i drift align from there - its normally not very far out.
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  #26  
Old 09-06-2012, 02:26 AM
knowledge (Student)
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Thank you for your suggestion.

Has anyone used the brand Silva, or to be more exact, the Silva Polaris?

Here is a link to it:

http://www.llbean.com/llb/shop/63609...s&catalogId=18

Thanks,

Knowledge
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  #27  
Old 09-06-2012, 06:46 AM
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Quote:
Originally Posted by knowledge View Post
Thank you for your suggestion.

Has anyone used the brand Silva, or to be more exact, the Silva Polaris?

Here is a link to it:

http://www.llbean.com/llb/shop/63609...s&catalogId=18

Thanks,

Knowledge
If it is a genuine Silva model you can't really go wrong.

But.....

That site looks like it is American. If it is then you need to make sure that the compass you buy is designed (or balanced) for use in the Southern Hemisphere. If I use a compass setup for Northern Hemisphere in the South, the needle or card will drag or jam against the housing.

Hope this makes sense.
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  #28  
Old 09-06-2012, 12:46 PM
knowledge (Student)
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One compass to use worldwide where ever you go?

I don't know too much about compasses... So can you buy a compass that you can use worldwide where ever you go? I plan to use my compass mainly in the US, which is where I am from by the way, and also around the Middle East and that whole part of the world.

Are the Silva compasses that are made in Sweden the good ones? What do you think about this type:

http://www.ebay.com/itm/190686949410...84.m1438.l2649

These are from the 1960s I believe.

Thank you,

Knowledge
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  #29  
Old 09-06-2012, 02:57 PM
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If you are in the Northern Hemisphere it is the same deal, make sure the compass you buy is balanced for the region you intend to use it.

Silva is a well known brand and their gear is good to excellent depending on how much you wish to spend and what you need the compass to do. There are other Swiss made brands of compass that have excellent reputations as well.

The model in your last post would be a great piece for collectors and probably still works well.

To complicate the issue a little further, if you intend to use your compass in the Middle East it might be better to get a model that can be used worldwide and is not as sensitive to zone changes. These models do exist but they can get quite expensive.

How much do you intend to spend?
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  #30  
Old 09-06-2012, 09:45 PM
knowledge (Student)
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To be honest, I don't intend to spend too much, but I do need it mostly for accuracy and precision. I don't want to spend more than $50 on a compass (maybe sometime in the future I will though) and I think I can get what I need for a lot less than that. The main thing I will be using the compass for is finding directions. If I need to find the direction of Southeast in a particular place, for example, I need it to be extremely accurate in this. Other than that, I do not plan on using it to read maps, etc. I currently use the sun and shadows to guide me in this, but if I can get an accurate compass (after being tested of course) then this will be great and it'll save me much time.

Is there a special name for those that work worldwide?

Thank you

Knowledge.
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  #31  
Old 18-06-2012, 12:16 PM
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It's hard to suggest what you need without knowing just what you need it for! If you need to take an accurate bearing from your position to a particular object, you should probably go for a sighting compass (for example at Silva here). They have a mirror to allow you to sight horizontally while reading the compass dial vertically. This will allow you to take bearings to within a couple of degrees or less, once it is calibrated appropriately. Test your compass by triangulating a known location using a map, also by repeating observations - do all the bearings converge on your location? I have used a similar model to the Silva Ranger CL for fifteen years, using it for geological mapping, geomorphological mapping and navigation on misty mountains in several places in the world. My compass was quite accurate enough to keep me on mountain ridges in mist and snow, or to triangulate outcrops/features of interest onto a 1:25000 map. I can't imagine what you would need to do that would require greater accuracy?

Mine's a Northern Hemisphere model and accurate sighting is more difficult (but not impossible) in the southern hemisphere as you end up having to tilt the housing to allow the needle to swing freely. Tilting the compass back to sight correctly introduces potential error. You shouldn't have such a problem if you're going from the US to the Middle East, using a NH compass - the change in needle tilt will be much less than travelling to the SH. Cairo and Kuwait are roughly the same latitude as Jacksonville FL and New Orleans, so you should have few significant needle tilt problems in much of the Middle East. Hope this helps!
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