When is the best time of year to have lunar and solar eclipses? and why?
There are eclipse seasons that occur about every six months. To have an eclipse, you need two things:
1- To be in a new moon phase for a solar eclipse or in a full moon phase for a lunar eclipse
2- To have the Earth, Sun and Moon all three perfectly lined up.
The first of these conditions happens every month. It's the second condition which is more rare. This is because the Moon doesn't orbit the Earth exactly in the same plane as the Earth orbits the Sun. The orbit of the Moon is inclined by 5 degrees with respect to the plane of the Earth's orbit around the Sun, which we call the plane of the ecliptic. Because of that inclination, the Moon keeps moving above and below the plane of the ecliptic. This means that the odds are pretty small that the Moon will happen to be in the plane of the ecliptic right at the full or new moon phase. The conjunction of these two events happens about every six months. At these times only are you likely to get an eclipse. It doesn't happen exactly every six months however, so the "eclipse season" shifts from year to year. You can see that by looking at a list of upcoming eclipses from the US naval observatory.
This page was last updated June 28, 2015.