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John says the celestial sphere is not polar aligned, and I say it is.
John says the stars do not change their positions on the
celestial sphere. I say they do.
This boils down to the definition of celestial sphere.
* * begin quotations * *
Just as we use the earth's poles and equator as reference marks on the earth, we can use corresponding reference marks on the sky.
The celestial poles and celestial equator are defined by the earth's rotation.
In the northern sky, [stars] appear to revolve around a point
called the north celestial pole, the point on the sky directly above
the earth's North Pole.
In fact, the celestial poles and equator are the basis for a
system of precise celestial coordinates much like the system of
latitude and lingitude on the earth,
But we must beware. These critical reference marks on the sky
are moving, and that can tell
us something new about the motion of the earth.
...earth's axis [precesses] in a conical motion, taking about
26,000 years for one cycle. Because the celestial poles and the
equator are defined by earth's rotation, precession changes
these reference marks.
Over centuries precession has dramatic effects. For example,
it makes the celestial poles move across the sky. Egyptian records
show that 4800 years ago the north celestial pole was near
the star Thuban (a-Draconis). The pole is now approaching Polaris and
will be closest to it about AD 2100.
* * end quotations * *
That's the definition of "celestial sphere" in all the astronomy
books.