Adapted compass

[Rogier]

Hi,

I am a first time hiker. I have bought the cheapest base plate compass I could find. While practising with it, I found it hard to do an accurate sighting. Therefore I adapted the compass with a slot to look through and a little mirror (a piece of a cd-rom) so that I can see the needle while sighting. Now I keep reading on web pages that hikers usually take the cheapest compass with them. Is there no need for such accuracy, am I doing something wrong, or what?

Regards,
Rogier

[cldphoto]

You're confusing precision with accuracy. Ideally, you want both, but if you can't have precision, you at least want accuracy. An accurate compass will point north. A precise compass will give you measurements within a fraction of a degree. However, just because a compass is accurate doesn't mean it's precise, and vice versa.

Will this work for you? Depends on your goal. If you're just hiking, it'll do. Since you have a cheap compass, it's not going to be precise; I'd be surprised if you got measurements closer than +/- 5 degrees. However, as long as it's accurate, it'll get you close enough that basic map reading skills will get you to your goal. [If you're planning on doing hard-core orienteering and navigation competitions, though, you need to spend some more money ad get a better compass.]

Your design accomplishes basically the same thing as my US Army lensatic compass (see below). Sure, it lacks tritium night sights (mmm, radioactivity) and mils (mmm, artillery), but it's better than nothing. :)

http://www.eliteforc.com/store/html/images/GILensaticCompass.gif

Just make sure you check the accuracy of your compass against something you know is accurate. I've seen cheap-o compasses that were completely off -- they didn't point anywhere near magnetic north.

[Sgathak]

Mmmmmm... Artillary:D

[blackdog]

Being a hiking newbie myself, I use a Suunto M-9 wrist compass in my daily work. It's basically a two notch system (like yours) with edge readout. The degrees on the edge of the disc that replaces the compass needle show through a window on the side of the housing. I just aim with the notches and read the numbers.

So far I haven't needed a higher precision than the 5 degrees of the M-9, probably because I don't move in long straight lines when I work. The maps I work with are very detailed too, so finding the position and direction is quite easy.

The things I miss in your design (when comparing) are:
1. The phosphorous disk.
2. The wrist mounting.

I can't see why your design wouldn't work for hiking. I mean, the Suunto isn't perfect either. Setting a bearing from maps is awkward because the compass isn't transparent. And the original strap just sucks. A hook&loop wristband works much better.

I like the light weight of the M-9, though, and the fact that I always have it on my wrist when I'm out there.

[Rogier]

Christian: right you are about the confision, and thanks for the tip. Great photo's on your website by the way.

Blackdog: also thanks for the tip, I think an elastic band will do for a wrist strap for now. As for the phosphorous disk, I will get around to that if and when I try my hand at night hiking. I will probably have another compass (M-9?) by then anyway.

Rogier

[blackdog]

Rogier, an elastic band will work much better for your design. But using one for the watch-like M-9 is pretty much impossible.

Nightlight... One thing you could try is to get one of those phosphorous kindergarten stars (the ones children might have above their beds) and hang it on the elastic strap. A LED-light is another option. Having one is a good idea anyway, I think.

[Rogier]

Ok, thanks again. I will give it a try. Always liked kindergarten :)