AAO image reference MISC 15. « Previous || Next »
Image and text © 1991-2002, Australian Astronomical Observatory, Photograph by David Malin.
As the earth spins beneath the stars they appear to move across the sky from east to west. However, if one looks in the direction of the celestial poles, the stars seem to circle a single point on the sky during the night. This is the position of the earth's axis of rotation projected into space.
If the photographs had been made at either of the geographical poles, from the Arctic or in Antarctica, this point would directly overhead, and the axis of rotation would passing vertically through the camera. If the picture had been made from the equator, both the pivotal points would be seen 180 degrees apart, on the northern and southern horizons.
These pictures were made from Siding Spring Observatory in Australia (left), and from the La Plama Observatory in the Canary Islands, so the pivotal points are about 30 degrees above their respective horizons, which reflects their geographical latitudes. In this mosaic, the images have been rotated so that the horizon of both images runs down the centre of the picture. More information on star trail photography is here.
Related images
AAT 5. Star trails southwest of the AAT dome
AAT 6. Star trails around the south celestial pole
MISC 5. Dawn and evening twilights reflected in the AAT dome
MISC 6. Moonset into cloud over the Warrumbungle Range
MISC 7. Star trails around the AAT dome, after Pinatubo sunset
MISC 11. Orion star colours, step-focus technique
MISC 12. Orion's belt rising over the lights of Coonabarabran
MISC 13. North celestial pole star trails
MISC 14. South celestial pole star trails
MISC 16. Southern Cross and Pointers, star colours - step-focus technique, long trails
MISC 18. The view to the north from Siding Spring
MISC 19. Sunset 'star' trail, the track of the setting sun
MISC 22. The AAT dome from the Director's Cottage.