|I wonder if I have too many compasses?|
In the second photo, the hockey puck is on the left, next is a chinese lensatic, then a U.S. army lensatic and the last one is the M2 compass, the same as the Brunton pocket transit, which also has level bubbles so that you can also measure vertical angles. This one is marked in degrees, most are marked in mils.
Make sure you get a compass with a card instead of a needle, one less thing to line up when measuring an azimuth. The exception is the M2 which has a needle but the scale on the body of the compass is marked backwards, increasing counter-clockwise. You line up the alidades mounted on the body with the azimuth to be measured and you read out the azimuth at the end of the needle from the backwards scale on the body.
--- On Tue, 11/6/12, Apache Runner
From: Apache Runner <email@example.com>
Subject: [NavList] Re: Accuracy of backpacking compass
Date: Tuesday, November 6, 2012, 8:07 AM
I have a Silva version that's similar to the Suunto in your attachment, including the mirror. I seem to only get about +/- 5 degrees with this, but I'm not using the technique you describe. Let me give it another shot.
On Mon, Nov 5, 2012 at 11:26 PM, Paul Dolkas <firstname.lastname@example.org>
One more opinion-
My favorite compass is a Suunto with a mirror – probably the same one you have. You can vastly improve the accuracy by painting a small black dot on the center of the pivot (see the attached photo). You line up the image of the dot in the mirror with the line on the mirror as shown, and you eliminate almost all the pointing error since the mirror is now perpendicular to your line of sight. Try it – you will be amazed. Much better than 5 degree accuracy, and super simple to use. Only thing missing from this model is a magnifying glass lens so you can read the fine print on a map.
Almost forgot – the mirror should be considered a nessesity for backpacking, since it doubles as an emergency signalling mirror. Don’t leave home without it.
Thanks for the advice, everyone. Now I know what I want for Xmas! My current hand-held is a Silva with a mirror and line on it. I think I can do about 5 degrees with it, but I could surely use one that gets down to 2 degrees. The students have an even rattier hand-held - amazing we can do anything with it!
I do have a military quality marine binoculars and spend a fair amount of time with them, but in backpacking situations it's too heavy for use. The curious, and not surprising issue is that I get knocked off a few degrees when I use them with my glasses. These binoculars do have the nice feature of a reticle in mils, which is helpful for determining ranges a bit more precisely than using finger widths.