As the earth rotates the stars appear to move across the sky, as do the more obvious Sun and Moon This effect is easily recorded by leaving a camera outdoors with its shutter open during the night. To make this picture, the camera was pointed to the southwest, towards the dome of the AAT, from the UK Schmidt building on Siding Spring Mountain in New South Wales, and the exposure was about six hours.
If the camera had been pointed due west (right of the AAT dome), the stars which are on the celestial equator would have made straight trails as they slipped below the horizon, instead of the curves seen here. The lights which can be seen on the mountain are in reality quite faint and are only recorded in exposures which last several hours.
Credit: David Malin/Anglo-Australian Observatory
Post by David Malin From Earth to the Universe team.
