Compasses

[A Jay]

Hi, shopping for compasses and have found some conflicting information regarding the sighting mirror feature.

One reviewer seemed to recommend against a sighting mirror early in the article, then recommend for a sighting mirror later in the article.

When recommending against, they said sighting mirror is useless in poor visibility conditions such as dark, rain and high winds. As well, they said that using sighting mirror produces parallax as you're not looking straight down the needle to the shed. They also say that backcountry users should NOT depend upon a sighting mirror.

However later in the article, the reviewer lists the sighting mirror in their list of recommended additional features for a compass. They say that a sighting mirror will reduce errors when going from eye to waist. However as I said, earlier in the article they said a sighting mirror can produce errors because of parallax.

So there is some conflicting information, and I've had some difficulty actually finding much information on the desirability of using a sighting mirror.

[wildwanderer]

Personally I don't think a sighting mirror is necessary and just adds bulk, weight and gets in the way when you place your compass on a map. Its very easy to take a bearing on a distant landscape feature using just a normal compass.

I find the simple plastic compasses are the best. Its nice to be able to see through the compass plastic to look at the map. Something with a printed distance scale is also nice.

The only bells and whistles feature I have on my compass is a declination adjustment notch. Saves all the 'hardcore' maths

[A Jay]

Personally I don't think a sighting mirror is necessary and just adds bulk, weight and gets in the way when you place your compass on a map. Its very easy to take a bearing on a distant landscape feature using just a normal compass.

I find the simple plastic compasses are the best. Its nice to be able to see through the compass plastic to look at the map. Something with a printed distance scale is also nice.

The only bells and whistles feature I have on my compass is a declination adjustment notch. Saves all the 'hardcore' maths

One of the articles called it 'Dangerous' maths, you avoid "dangerous maths" on the trail when you have a declination adjustment.

[GPSGuided]

First question is, what will you use the compass for? For general navigation, there’s really no need for the sighting mechanism and the potential precision. As said above, it also adds extra bulk that’s unnecessary. A good quality base compass with declination correction is much more useful. Particularly recommend Suunto’s upper end models.

[slparker]

I have been using a compass for 30 years and have never heard of declination adjustment.
I always work out my bearing after adjusting for grid-magnetic variation and local magnetic drift - I prsume that it has something to do with this.
If so, you surely still need to do the 'dangerous maths' of working out these differences?

[A Jay]

I have been using a compass for 30 years and have never heard of declination adjustment.
I always work out my bearing after adjusting for grid-magnetic variation and local magnetic drift - I prsume that it has something to do with this.
If so, you surely still need to do the 'dangerous maths' of working out these differences?

Compasses with declination adjustment are a large part of the compass market now. These compasses have a key and a hole on the reverse side of the baseplate where you adjust the declination and it stays adjusted. You don't have to adjust manually anymore if the declination remains the same.

It's an extremely common feature in a compass these days, although according to TraditionalMountaineering, the Silva Ranger for the last 30 years was the only compass that had the declination adjustment. Now, they're everywhere and virtually every guide's suggesting navigators use a compass with declination adjustment to avoid the "dangerous" maths in the field, a matter of safety.

[Neo]

I picked a Suunto A-30.

Second most basic model. Its been fine to use with a topo and do handheld bearings.

Has a magnifier, glow in the dark bezel and a circle&triangle for tracing if you want to.

Silva is popular but I read a few reviews of them not being accurate/solid.

Just turn the bezel to suit your maps declination (11° east coast usually).

About $36 online

[slparker]

I have been using a compass for 30 years and have never heard of declination adjustment.
I always work out my bearing after adjusting for grid-magnetic variation and local magnetic drift - I prsume that it has something to do with this.
If so, you surely still need to do the 'dangerous maths' of working out these differences?

Compasses with declination adjustment are a large part of the compass market now. These compasses have a key and a hole on the reverse side of the baseplate where you adjust the declination and it stays adjusted. You don't have to adjust manually anymore if the declination remains the same.

It's an extremely common feature in a compass these days, although according to TraditionalMountaineering, the Silva Ranger for the last 30 years was the only compass that had the declination adjustment. Now, they're everywhere and virtually every guide's suggesting navigators use a compass with declination adjustment to avoid the "dangerous" maths in the field, a matter of safety.

Well that's where i am confused, what exactly are you adjusting for?
If it is the difference between grid and magnetic north it is map and region specific, so there is no 'set and forget' declination to set. You still have to do the 'dangerous maths' ( if you can call substraction and addition 'dangerous') every time you use a different map in a different area.
I get the point of settting a declination so you don't have to keep working out the magnetic variation when converting a bearing from grid to magnetic but it's hardly difficult maths, especially if you calculate the mag variation for that year and pencil,that onto the map.

[A Jay]

I picked a Suunto A-30.

Second most basic model. Its been fine to use with a topo and do handheld bearings.

Has a magnifier, glow in the dark bezel and a circle&triangle for tracing if you want to.

Silva is popular but I read a few reviews of them not being accurate/solid.

Just turn the bezel to suit your maps declination (11° east coast usually).

About $36 online

Thanks Neo. By the way, I like your handle from The Matrix, cool movie!

I actually have been preferring the Suunto over the Silva, and the experienced guides seem to like the Suunto too.

Just to confirm, the Suunto A-30 is second from the bottom and not second from the top, right?

I think the Suunto M3-G is the best one without sighting mirror, it has the global needle. I'm not sure if I can afford one with the global needle, but if I'm not mistaken, a global needle would make the needle more reliable because it's less likely to stick and stuff, right?

[A Jay]

I have been using a compass for 30 years and have never heard of declination adjustment.
I always work out my bearing after adjusting for grid-magnetic variation and local magnetic drift - I prsume that it has something to do with this.
If so, you surely still need to do the 'dangerous maths' of working out these differences?

Compasses with declination adjustment are a large part of the compass market now. These compasses have a key and a hole on the reverse side of the baseplate where you adjust the declination and it stays adjusted. You don't have to adjust manually anymore if the declination remains the same.

It's an extremely common feature in a compass these days, although according to TraditionalMountaineering, the Silva Ranger for the last 30 years was the only compass that had the declination adjustment. Now, they're everywhere and virtually every guide's suggesting navigators use a compass with declination adjustment to avoid the "dangerous" maths in the field, a matter of safety.

Well that's where i am confused, what exactly are you adjusting for?
If it is the difference between grid and magnetic north it depends on which map you are using so there is no 'set and forget' declination to set. You still have to do the 'dangerous maths' ( if you can call substraction and addition 'dangerous') every time you use a different map in a different area.

Yes, it adjusts the GM, so between grid and magnetic north.

What I meant was, you can adjust it, then forget it while you're in the same declination area. If you go to an area with a different declination, you then use the key and adjust it again to the new declination. So it's only "forget" while you're in the same declination area. But you can use the key to adjust the declination as many times as you want and it will be adjusted to that declination until you adjust it again.

You only have to do the maths once for any given declination, and that will usually be in the comfort of home before you head out. Only time in the field you'd have to readjust would be if you're literally moving to an area with new declination.

[Neo]

Matrix? Please explain. I write my own material!

Yeah second from the bottom or base model. I didn't know/want to spend or over do it on my first compass. Pending future accidents this one may see me out! (southern hemisphere)

[A Jay]

Matrix? Please explain. I write my own material!

Yeah second from the bottom or base model. I didn't know/want to spend or over do it on my first compass. Pending future accidents this one may see me out! (southern hemisphere)

YOU DO YOUR OWN MATERIAL????? YOU ARE THE ONE!!!!!!!

I looked for it on ebay and it confuses me because firstly there's prices between $25 and $80 for it, and secondly I'm not sure if I'm viewing the same compass, because while it says "A-30", there are variations of numbers and descriptions associated with the "A-30". Are there different types of A-30s?

For example, here are two A-30s, one at $26, and the other at $76. One says A-30 Field, and the other says A-30 Explorer:

http://www.ebay.com.au/itm/Suunto-A-30- ... SwvflZUDIh


http://www.ebay.com.au/itm/Suunto-A-30L ... SwhlZYuEyv

[Neo]

Will see if i have the receipt.

Were two options and one shop confirmed their model.

[Neo]

https://prospectors.com.au

[A Jay]

Thanks, I like that shop, and it's a reasonably priced compass, $30 and is said to be the best brand for reliability, which for me is a very important consideration. I may end up going with that one, I doubt at this stage I can afford an more expensive one.

[wildwanderer]

On the subject of compasses. My Suunto M3's liquid has long since drained out of the compass with a few crystalline flakes remaining. Either that or somehow salt got into the bezel area.

Does anyone know if its possible (and how)to replace the liquid ? Compass still works fine, but Id prefer the liquid in there for needle stability if there is a way

EDIT. actually looking closely the liquid may still be there, its a bit hard to tell.. but there are these flakes in the liquid like salt ..

[A Jay]

On the subject of compasses. My Suunto M3's liquid has long since drained out of the compass with a few crystalline flakes remaining. Either that or somehow salt got into the bezel area.

Does anyone know if its possible (and how)to replace the liquid ? Compass still works fine, but Id prefer the liquid in there for needle stability if there is a way

EDIT. actually looking closely the liquid may still be there, its a bit hard to tell.. but there are these flakes in the liquid like salt ..

I could be wrong, but I would have thought you'd have known if liquid had began to go out because there might have been air bubble develop.

In my research, they say not to get ones with air bubbles, they can be inaccurate, and as you probably already know, they develop due to exposure to very cold temps. Anyway that's off subject.

But I would have thought you'd know if liquid was going due to air bubbles. Could be wrong though.

[wildwanderer]

On the subject of compasses. My Suunto M3's liquid has long since drained out of the compass with a few crystalline flakes remaining. Either that or somehow salt got into the bezel area.

Does anyone know if its possible (and how)to replace the liquid ? Compass still works fine, but Id prefer the liquid in there for needle stability if there is a way

EDIT. actually looking closely the liquid may still be there, its a bit hard to tell.. but there are these flakes in the liquid like salt ..

I could be wrong, but I would have thought you'd have known if liquid had began to go out because there might have been air bubble develop.

In my research, they say not to get ones with air bubbles, they can be inaccurate, and as you probably already know, they develop due to exposure to very cold temps. Anyway that's off subject.

But I would have thought you'd know if liquid was going due to air bubbles. Could be wrong though.

I think your right. The liquid is probably still in there. Got no idea where the flakes came from though... doesn't seem to be any lettering etc crumbling off

[A Jay]

On the subject of compasses. My Suunto M3's liquid has long since drained out of the compass with a few crystalline flakes remaining. Either that or somehow salt got into the bezel area.

Does anyone know if its possible (and how)to replace the liquid ? Compass still works fine, but Id prefer the liquid in there for needle stability if there is a way

EDIT. actually looking closely the liquid may still be there, its a bit hard to tell.. but there are these flakes in the liquid like salt ..

I could be wrong, but I would have thought you'd have known if liquid had began to go out because there might have been air bubble develop.

In my research, they say not to get ones with air bubbles, they can be inaccurate, and as you probably already know, they develop due to exposure to very cold temps. Anyway that's off subject.

But I would have thought you'd know if liquid was going due to air bubbles. Could be wrong though.

I think your right. The liquid is probably still in there. Got no idea where the flakes came from though... doesn't seem to be any lettering etc crumbling off

Perhaps your compasses micro-climate is compromised on account of the seals losing integrity. Perhaps time to fix it or get a new compass. I do hear that seals do lose integrity a lot with compasses, quite a common thing. I read liquid can indeed leak out through the seals, although if the seals are only a little bad then perhaps liquid can't get out but air can get in, which affects the liquid in their. If the liquid contains some salt in the water so the needle floats better, then maybe the exposure of even a little outside air through the seal might result in some crystallization. That's by bro-physics, or bro-chemistry I should say lol

[Orion]

A friend bought me a toy "weather lab" a few years ago.



It was kind of a joke but I assembled it, put it outside, and mostly forgot about it. Recently, as I prepared for a trip, I decided that a compass would be a good idea. But due to the terrain I didn't think I needed a highly precise compass. I just needed to be able to determine roughly which way north is for those rare times when I might get a little confused.

So I took some shears and cut the tiny button compass out of my weather lab, filed down the rough edges, and took that with me.

And it did exactly what I hoped it would do. It capably pointed north, plus or minus about 15° -- just what I needed a few times on the trip.

[A Jay]

Haha, for some reason I kinda find your post a bit funny, but I honestly don't know what the moral of the story is. Button compass from weather station was used, and worked to the nearest 15-degrees. That's good!!! Mmm, I'm missing something. Do you mean I don't need anything too fancy?

[Orion]

Do you mean I don't need anything too fancy?

I don't know what level of accuracy you need.

The point of my story is that you should fit the tool to the task.
It would have been silly for me to have carried a sighting compass.
But that doesn't mean you don't need one.

[A Jay]

Do you mean I don't need anything too fancy?

I don't know what level of accuracy you need.

The point of my story is that you should fit the tool to the task.
It would have been silly for me to have carried a sighting compass.
But that doesn't mean you don't need one.

You should have got to the point to begin with instead of taking the laboured, inaccurate and deviant route around. Your post was about as accurate as the button compass you were using.

[Orion]

Your post was about as accurate as the button compass you were using.

They were each as accurate as necessary for the circumstances.

[A Jay]

Your post was about as accurate as the button compass you were using.

They were each as accurate as necessary for the circumstances.

Why don't you stick your head in the weather station, that should clear your sinuses and improve your accuracy. Replace the button compass so you can tell the direction.

[Orion]

Why don't you stick your head in the weather station, that should clear your sinuses and improve your accuracy. Replace the button compass so you can tell the direction.

You're projecting your own needs. I was quite happy with the accuracy.

[A Jay]

Why don't you stick your head in the weather station, that should clear your sinuses and improve your accuracy. Replace the button compass so you can tell the direction.

You're projecting your own needs. I was quite happy with the accuracy.

As it stands, I too am happy. Your accuracy has improved out of sight!

[Neo]

I liked the post.

On a recent trip away mum got me a gift. Is a paracord bracelet with whistle, button compass and tiny fire steel.

It's the thought that counts!

[Neo]

There is a method to use a watch face to determine north. Someone correct me if I'm wrong:

Point 12 at the sun, then north is between the hour and the minute hand [?]

[peregrinator]

But don't forget the declination for Summer (Daylight Saving) time. You do not need to apply any dangerous or otherwise arithmetic to make the calculation. You point 1 o'clock to the sun.