High up on the roof of the incredibly sophisticated Amundsen-Scott South Pole Station, there exists an extremely low-tech piece of equipment: The Campbell-Stokes Sunshine Recorder. Photos.
The Campbell–Stokes recorder (sometimes called a Stokes sphere) is a kind of sunshine recorder. It was invented by John Francis Campbell in 1853 and modified in 1879 by Sir George Gabriel Stokes. The original design by Campbell consisted of a glass sphere set into a wooden bowl with the sun burning a trace on the bowl. Stokes’s refinement was to make the housing out of metal and to have a card holder set behind the sphere.
The unit is designed to record the hours of bright sunshine which will burn a hole through the card.
This basic unit is still in use today with very little change. It is widely used outside the United States, where the Marvin sunshine recorder is generally the instrument used by the National Weather Service.
A few photos of the unit currently recording sunshine at the South Pole: