The Rotating Earth Home

At one time men believed that the stars rotated around the Earth.  These pictures show why.  They were made by pointing a camera at the north celestrial pole and effectively leaving its shutter open for several hours.  To the shephards seeted on the hillside all night and looking up must have noticed the stars all moving slowly across the sky.  Today we believe that the movement is an illusion caused by the slow rotation of the Earth carrying the observer with it.

The rotating Earth makes the stars appear to revolve.
This picture was made by attaching a lens from a security camera to my DFK camera and pointing it at the celestrial north pole.  I left it taking 27.6 second exposures every 28 seconds for the whole of the night.  By morning I had four hours-worth of images before the sky brightened and clouds moved in.  This picture was then produced by stacking 527 pictures using the if-lighter option in K3CCDTools.