Eclipses can only happen at New Moon (for a solar eclipse), or at Full Moon (for a lunar eclipse), when the Earth, Moon and Sun actually line up.
(Eclipses; can only happen; L:at New Moon (for a solar eclipse), or at Full Moon (for a lunar eclipse; T:when the Earth, Moon and Sun actually line up) (the Earth, Moon and Sun; actually line up; )
Eclipses the Earth, Moon and Sun
can only happen actually line up
L:at New Moon (for a solar eclipse), or at Full Moon (for a lunar eclipse T:when the Earth, Moon and Sun actually line up