NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2025 Mar 28, 18:54 -0700
As you noted in your first message, it's "some kind of parallax", right? The Sun isn't wobbling, but the Earth is on the other end of the balance beam of the Earth-Moon system. So if the Moon goes up, above the ecliptic, the Earth goes down. Makes sense. And it goes down by a factor of about 1/81 of the Moon's "up" motion since the Moon is about 81 times less massive than the Earth. But this wobble is reflected in the Sun's apparent motion, and the Sun is 400 times further away than the Moon.
Hitting JPL Horizons again, if we add the Moon's ecliptic latitude, there's clearly an alignment, and the scale is good --about 81 times smaller for the mass difference and then 400 times smaller again, due to the much greater distance to the Sun. But the match isn't quite right. See the image below... What explains the differences then? And I'm still interested in that funny wobble from the last graphic. :)
Frank Reed
