[geocentrism] Re: Two spin axes of Earth?
- From: Neville Jones <njones@xxxxxxxxx>
- To: geocentrism@xxxxxxxxxxxxx
- Date: Wed, 14 Nov 2007 09:06:08 -0800
Dear Regner,
The point of the two diagrams was that each illustrate two types of motion, depending upon how you view them.
In particular, the camera is always fixed to an immovable mount, and it is the World itself that moves.
In Camera movement 2 negative.gif, attached again for your convenience, we have the essence of the two-axis argument.
View it one way, and the optical axis of the camera always points toward the celestial polar axis, irrespective of the time increments. This explains what we see, night after night, hour after hour, minute by minute, whether sidereal or solar. View it another way and the optical axis always points toward the ecliptic polar axis (with the proviso, of course, that we tilt the paper, because the celestial and ecliptic axes are not coincident), each 24-mean-solar-hour step. This explains what we should see (but do not), for exactly the same reason.
In the first viewing mode, the large circle is the World, with the centre of the World at the centre. In the second viewing mode, the small circles represent individual positions of the World, with the large circle being the World's alleged orbit and the centre of the diagram being the centre of the Sun. (The slight eccentricity of the orbit is not relevant to this discussion.)
Note that the camera can be rotating about the celestial axis daily, but still align its optical axis with the ecliptic polar axis at tropical day increments. The only difference we should expect to see between the two sets of star trails is that the annual ones would be only roughly circular.
Neville
Quoting Neville Jones <njones@xxxxxxxxx>
>
> Regner,
>
> Thank you. And I accept your inference that the orbit, at this inclination,
> ought strictly to be elliptical.
>
Okay, so the axis perpendicular to the screen is the daily rotation axis
of the Earth, and the orbit of the Earth around the Sun should be foreshortened
by the 23.4' angle between that axis and the ecliptic axis.
> However, there is a second interpretation of the figure. That this does not
> depict one camera, but 16 cameras scattered around the World, all with their
> optical axes parallel with the celestial polar axis.
>
Okay - so all the cameras are pointed at the viewer of your figure?
And each of the 16 instances of Earth, has 16 cameras mounted, equidistantly
on the equator?
That is not a different view of the same thing - that's a different
scenario.
> In this case, the time
> intervals, for rotation about the celestial polar axis (in the plane of the
> paper/screen), can be sidereal or solar. Agreed?
>
The time intervals between the 16 instances of Earth that you depicted in your
two figures? They are obviously unaffected by where you put a camera...?...
I don't think I quite get your question.
Regards,
Regner
Attachment:
Camera movement 2 negative.gif
Description: GIF image
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