Do lunar eclipses only happen at the descending node of the lunar orbit?
I have not thought about this very much, but there are in principle two locations where eclipses can occur. These are the points in the lunar orbit that intersect the ecliptic plane where the sun moves in the sky. These are called the Ascending Node and the Descending Node. The Ascending Node is the one located opposite of the Earth from the Sun and it is here that lunar eclipses occur. The Descending Node is between the Sun and the Earth and it is here that solar eclipses can occur. Because the orbital plane of the Moon, and so the so-called line of nodes, rotates once every 18 years, the above nodes, can switch places. So, the more complete answer is that lunar eclipses can also happen at the Ascending Node.
