Help envisioning celestial great circle apparent movement?

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Help envisioning celestial great circle apparent movement?

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1drbubbles
març 27, 2011, 10:39am

I have always skipped over making the connection between the terrestrial and extra-terrestrial perspectives of the ecliptic, celestial equator, and galactic planes simply because, while I can envision each individually, I have a hard time conceiving the relation between the two (extra-/terrestrial) perspectives. But the chapter I'm currently reading in When They Severed Earth From Sky is heavy on the effect of polar precession in the apparent timing and positioning of the equinoces and solstices, so I've decided to try to comprehend them once and for all.

I understand viscerally that the galactic plane doesn't move with respect to the constellations, and that the celestial equator does, during precession of the poles. It's the ecliptic that I haven't yet viscerally understood. Precession doesn't make the ecliptic plane appear to move relative to the background constellations, right? Or does it? It's the relative scale of earthly and interplanetary space that's throwing me, I think; on interplanetary scales, I think that parallax due to polar precession would not be enough to make the ecliptic seem to move, but I'm so used to changes in location making a difference in perspective on Earth that I'm having a tough time convincing myself viscerally of the truth of that.