What conditions are needed for a lunar eclipse?

Answer 1

• Partial Lunar Eclipse

A portion of the Moon passes through the Earth's umbral shadow. These events are easy to see, even with the unaided eye.

• Penumbral Lunar Eclipse

The Moon passes through the Earth's penumbral shadow. These events are subtle and quite difficult if not impossible to observe. During a penumbral eclipse the moons light is dimmed but does not go dark due to the fact that the penumbral shadow is not dark enough to black out the sun's light. A penumbral eclipse is sometimes referred to as an appulse eclipse.

• Total Lunar Eclipse

The entire Moon passes through the Earth's umbral shadow. During the time of totality the moons color may change to a dull copper tone, an effect caused by earth shine or reflected earth light. The moon can stay in the umbrals shadow for as long as 90 minutes.A lunar eclipse happens when the Moon passes through the Earth's shadow. Earth always has a shadow, which is created by the Sun. On those rare occasions when the Moon, Earth and the Sun are all lined up just right, the Moon passes through this shadow.This would happen every full moon if the Moon orbited around the Earth in the same plane as the Earth orbits around the Sun. The Moons orbit, however, is tilted about 5 degrees above the Earth-Sun plane. This tilt itself, however, rotates, allowing eclipses to happen when the tilt of this plane lines up with the Earth-Sun plane, blocking sunlight.

Answer 2

A lunar eclipse occurs when the Earth comes between the Sun and the Moon, casting a shadow on the Moon. Therefore, the conditions needed for a lunar eclipse are: a full moon phase, with the Moon on the opposite side of the Earth from the Sun, and the alignment of the Sun, Earth, and Moon on the same plane.