Written by Mike Stewart
So how do you find your way across a frozen white landscape with no landmarks, no signs, no place names, and changing topography?The same way you do when out in the open ocean, far from land. In fact, we are using the same two tricks that I use when I’m on the ship. One is very modern, instant, and easy… and the other is old fashioned, time-tested, and a little slower. Both give you the same result: your position. I bet you’ve already guessed what the first tool is…
Here’s a photo of Chris’s navigation equipment, mounted on his handlebars. The large GPS is powered through the machine’s cigarette lighter, the small GPS is battery powered. Chris has programmed in the exact waypoints that you see when you click on “The Route” tab here on our wordpress site. These are each of the places that we plan to go to do our measurements. These exact locations are where Carl Benson, renown snow physicist and researcher, went during his traverse in the 1950’s. We hope to document how much the ice sheet has changed since he was there, so it’s extremely important that we get to exactly the same latitude and longitude where he stood. Chris follows his course very carefully (on that tiny little GPS screen!) and brings us right where we want to go.
I’m in charge of the old fashioned method, calculating our position by using the sun. Here’s a pair of photos showing the tool that is used: a marine sextant. Those of you who have used a sextant before will notice that I am not looking through the normal eye piece, I have
a little gadget mounted there called an “artificial bubble horizon”. And it’s exactly what it sounds like, a small bubble in the lens lets me know when I am looking perfectly level. Even though the ice sheet looks completely flat, it is not a true horizon in the way that the surface of the sea is, so we use this jazzy lens which was originally made for air pilots to navigate while flying above the clouds, nearly 100 years ago!
A LITTLE bit slower than glancing at a GPS screen, huh?!! But, if the world’s GPS system were ever to quit working, our expedition would not be lost. Mariners use a special formula called a “sailing” to compute what heading to steer on the compass when they want to go from point “A” to point “B”. I also have this one programmed in, so if we needed to head back to Summit Station, we could do it with a sextant and a compass (but I would have to get off the snow machine to use the compass… the engine would mess up the compass needle reading!). For the nerdier navigators in the audience, check out the declination (map term) or variation (chart term) of the area where we are going! I also have all of these numbers along with me!
I finish with a fun set of pictures of the two navigators after arriving at our station today. It’s a rewarding (and extremely critical!) part of our daily life out here. If you have any navigation questions, you’re looking at a couple of nav-nerds, and we’d enjoy sharing more with you.