ecliptic limits

The maximum angular distances the Sun or Moon can be at full or new Moon from the points where the Moon's orbit crosses the ecliptic (the "nodes") in order for an eclipse to be possible. If the Moon's orbit coincided with the ecliptic, a solar and lunar eclipse would be observed at each new and full Moon, respectively. Since the Moon's orbit is inclined at 5° to the ecliptic and the apparent diameters of the Sun and Moon are only half a degree, eclipses can occur only when the Earth, Sun and Moon are lined up in space, or very nearly so. From the point of view of an observer on Earth, this means that both the Sun and Moon must be within a certain angular distance of one of the nodes of the Moon's orbit. For a lunar eclipse to occur, the Moon must be within 24° of its node; the Sun must be within 37° of the node for a solar eclipse to take place.