Caption: A cross-sectional side-view diagram of the Moon's orbit.

Features:

1. The following keywords are useful for the interpretation of the diagram:
   ecliptic plane, ecliptic pole, Earth, Earth's axial tilt (AKA obliquity), Earth's axis, Earth-Moon system, Earth radius, Moon, Moon's orbit, orbit (elliptical orbit), orbital inclination.

2. The Earth and Moon are approximately to-scale relative to each other, but the Earth-Moon distance is not-to-scale relative to the Earth and Moon.

3. The mean Earth-Moon distance (i.e., the mean orbital radius of the elliptical orbit) is actually 60.3229 Earth equatorial radii ≅ 60 Earth equatorial radii (384,748 km) (see Wkipedia: Orbit of the Moon).

4. The Moon is shown at the highest angle (5.14°) of its orbit relative to the ecliptic plane.

5. As the Moon orbits, it oscillates between 5.14° and -5.14° from the ecliptic plane.

6. During the oscillation, the Moon is usually more than 1 Earth radius from the ecliptic plane.

7. Consquently, the Moon and its shadow (including umbra, penumbra, and antumbra) are usually NOT in the planar layer that is 1 Earth diameter thick that is centered on the ecliptic plane.

8. This means that lunar eclipses and solar eclipses cannot usually happen when the Moon, Earth, and Sun are aligned when projected onto the ecliptic plane.

9. Eclipses can only happen when the line of nodes (AKA node line) is approximately aligned with the Earth-Sun line.

   The line of nodes is the line that passes through the two intersection points of the Moon's orbit and the ecliptic plane.

10. The exact alignment occurs every 173.31 days and the time frame around exact alignment when eclipses can happen is 31 to 37 days (see Wikipedia: Eclipse season: Details). This time frame is called the eclipse season.

11. If counterfactually the orbital inclination of the Moon were zero, there would be one total solar eclipse/annular solar eclipse and one total lunar eclipse every lunar month---and then eclipses would be just so simple.