Polar Star
Fig. 29: The star polaris, also called northern polar star above firs. The stars are rotating 15 °/h counter-clockwise around the north celestial pole. The brightest star near the north celestial pole is currently Polaris. In 12'000 years it will be Vega. Tha'ts due to the precession of the earth's rotational axis. Combination of 15 exposures with 4 minutes exposure time at ISO 400 each. Nikon D3; Δt=240 s; f=17 mm; f/3.5; ISO 400; 6 February 2011 01:55:25