2015 May 8
When Vega is North
Image Credit & Copyright: Miguel Claro | Dark Sky Alqueva
Explanation: In only about 12,000 years
Vega will be the North Star, the closest bright star to our fair planet's
North Celestial Pole. By then, when you fix your camera to a tripod long exposures of the night sky will show the concentric arcs of star trails centered on a point near Vega as Earth
rotates on its axis. Of course, presently the bright star conveniently near the North Celestial Pole is
Polaris, but that will change as the Earth's
axis of rotation precesses, like the wobble of a spinning top with a precession period of
about 26,000 years. If your camera is ready now and you don't want to wait 12,000 years for Vega to be the North Star,
consider this ingenious demonstration of contemporary star trails (left) versus star trails reminiscent
of the year 14000 CE. Both were recorded this April at the Alqueva Dark Sky Reserve in Alentejo, Portugal. To produce the more Vega-centric star trails of the distant future, astronomer Miguel Claro combined the rotation of two startracking camera mounts to create the apparent shift in planet Earth's North Celestial Pole.
http://apod.nasa.gov/apod/ap150508.html
