Well, you're probably going to be sorry you asked, but here goes. After watching some programs about Lewis and Clark and their exploration and mapping of the western US I became curious about how they were able to do that. I learned they uses a sextant among other devices. Having wondered how sextants operate, I did a little research on the Internet and then (naturally for me anyway) had to have one and purchased a Davis Mark 15 sextant which just arrived an hour ago. So for the foreseeable future I'll be playing with my new toy and learning how to use it. It will join the surveying transit I bought a year or so ago as my location/mapping toys. What can I say, I have this anal curiosity about how things work and then have to have one (when reasonably possible).