Please also notice that the values of observed
celestial pole offsets (dotted series) are slightly different in both figures.
This ancient sacral preoccupation with taking supernatural direction from the spirit of the
celestial pole, literally bringing an aspect of numinous heaven down to earth, like the practical use of the Dipper's handle as a clock-hand and the keying of lunar mansions to the culmination of circumpolar stars, survived on a liminal level to inspire seminal metaphors about charismatic potency, until by early imperial times both Taiyi and the Celestial Thearch di experienced a major resurgence of devotional interest.
Caption: To make the photograph used for the alignment process, you can attach the camera anywhere on the telescope tube or moving parts of the mount and point it toward the
celestial pole. A sturdy camera mount is highly recommended.
The data jumps above 10 [micro]as and changes in trend below 10 [micro]as/a are detectable in
celestial pole offset with accuracy better than 10 [micro]as and 16 [micro]as/a.
One good way to determine the exact location of the
celestial pole is to use a fixed camera to make a time exposure of the sky and note the point that the stars appear to revolve around.
For the nutation (
celestial pole offsets), P = dX + idY in celestial frame, very similar equations hold
All FCN models are constructed based on the analysis of the
celestial pole offset (CPO) time series obtained from very long baseline interferometry (VLBI) observations of extragalactic radio sources.
Earth's rotation makes the stars appear to circle the north
celestial pole in this July 1998 time exposure from the shore of Lake Zaboi in the Balkan state of Montenegro.
Rotating the mount around its polar axis tells the software where the mount's rotational axis is versus where the actual
celestial pole is.
Better agreement with Very Long-base Interferometry (VLBI)-based
celestial pole offsets (CPO) was achieved for the atmospheric/oceanic data from U.S.
Bootes lies behind Ursa Major, the Great Bear, and appears to be driving the Great Bear around the north
celestial pole.
But the Southern Cross served as a good omen to Christian navigators, and it was practical, too: its long shaft points to within a few degrees of the south
celestial pole. And in time navigators learned to find their way using many other bright southern stars.