Wednesday, 21 November 2012

South Pole

Someone said to me recently that when Amundsen reached the South Pole in 1912 he planted the Norwegian flag, then sent men out north, south, east and west, 5 miles in each direction, to take readings to confirm his position. In fact they discovered he was a few miles out, and he moved the flag to a new position.

This got me wondering, what instruments did they use, and what degree of accuracy could they achieve?


  1. i had always thought that, being a skilled mariner, Amunsden and his colleagues used sextant and dead reckoning. In which case a few miles out would be not bad, and the position would be refined over a few days. however to do so they needed to have a quality timing source, and I wonder how they did this. There was good daylight

  2. Actually, Amundsen was a great navigator having developed his techniques in Norway and Greenland. He used a sextant, with a mercury bath to give a true horizon for celestial observation in conjunction with a good chronometer for position, and a non magnetic sledge and good magnetic compass with a wheel distance measuring device for tracking.

    His observations were excellent for determining latitude, but of course longitude determination close to a pole is very difficult as the meridians converge to a point. Amundsen would have been able to determine his position position to better than a mile with good observations from a static observation point. When I was in navigator training we had to do many practise observations on the ground before doing them in the air, and a position to a mile with a hand held bubble sextant wasn't difficult.

    Most of the forgoing can be found in Roland Huntford's book "Scott and Amundsen" which is very readable albeit hard on his view of Scott's "stiff upper lip incompetence".

    Chris R

  3. Thanks, Chris, and Peter. That's very informative. I take your point, Peter, there was good daylight, as they were at the S Pole in late December, mid-summer. Presumably the sun was above the horizon 24-hours a day, very handy for taking lots of observations.

    Salutary to read that 'position to a mile' was good, in the vast space of Antarctica, compared to our experience nearer home, with maps etc, even before GPS. Have to admire navigators (near and far!).


Note: only a member of this blog may post a comment.