Last year I started getting more involved with cave surveying, and picked up a Suunto Twin (the combination unit with the prisms on top).
I like it, but sometimes I find it tough making sure my eye is square-on to the compass to avoid parallax errors. I have seen other cavers using Suunto's sister instrument, the Tandem. I've only had a brief play with one, but it's sighting system seemed slightly easier to use and possibly more precise.
I wonder if I should "upgrade" to a Tandem..?
On a side note, has anyone taken their compass and gone surveying in other parts of the world? If so, did you find it difficult to get accurate bearings because of magnetic dip and what (if anything) did you do about it? Considering most survey shots in caves aren't perfectly level anyway, what if you just manually compensate for the dip by tilting the compass slightly?
[FYI - magnetic dip is experienced when (for example) a compass disc manufactured for the northern hemisphere has a tendency to dip downwards toward the north pole when used in the southern hemisphere.]
Any comments?