Author Topic: Lunar Orbit Q&A  (Read 841 times)

Offline wolfpack

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Lunar Orbit Q&A
« on: 08/24/2017 07:47 PM »
In light (pun intended) of the recent eclipse in the United States, I'm sure many of us are more aware of our moon's orbit about the Sun and Earth than we were before. It actually is kind of complicated!

My first question - I get the ecliptic and the Moon's inclination to it and the Earth's inclination. What I'm having trouble visualizing is how the lunar nodes precess. What's the right way to think about this?

Offline Proponent

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Re: Lunar Orbit Q&A
« Reply #1 on: 08/25/2017 02:23 PM »
Try this.  Picture the moon's orbit as a (slightly elliptical) disk inclined 5o to the ecliptic.  Now imagine that disk rotating about an axis perpendicular to the ecliptic once every 18.6 years.  If we view the ecliptic from the North (from "above," as people usually think of it), the rotation is clockwise.