A lunar eclipse occurs when Moon enters the Earth's shadow. It occurs on a full moon. A solar eclipse occurs when the Moon comes in between the Sun and the Earth. It occurs on the new moon. They do not happen every on every full moon day or on every new moon day because the earth's orbit around the sun is not in the same plane as the Moon's orbit around the Earth.
Moon’s orbit is 5ο tilted than earth’s orbit around the sun. That’s why they don’t come in each other’s orbit very often.
Rate this question :