In general, a solar eclipse should be observable every new moon and a lunar eclipse every full moon, i.e. every month. However, this is not the case because the Moon’s orbital plane is tilted at an angle of 5 degrees to the Earth's orbital plane. Therefore, the Sun, Earth and Moon are only exactly in line when the Moon is close to the points where the orbit of the Moon crosses the Earth's orbit (nodes of the orbit of the Moon). Most of the time, however, the Moon is outside the Earth’s orbital plane. Fully illuminated by the Sun in space, as a full Moon, it passes under or over the Earth's shadow, or the shadow of the New Moon misses the Earth under or over its orbit.