During the Moon’s orbit around the Earth, it will occasionally pass through the Earth’s shadow, or will cast its shadow on the Earth. These events are known as lunar eclipses and solar eclipses, respectively. Lunar eclipses occur when the Moon passes through the Earth’s shadow. Because the Moon has to be on the opposite side of the sky from the Sun for this to occur, a lunar eclipse can only take place during the full moon phase. During a lunar eclipse, the Earth’s shadow will travel across the face of the Moon, appearing as though a bite has been taken from it.  At total eclipse, the Moon will not darken completely but instead glow deep red because the Earth’s gravity will refract (bend) a small amount of light from the Sun onto the lunar surface. Because the Earth casts a relatively large shadow, lunar eclipses occur a couple of times a year and are visible to large regions on the Earth, lasting up to 100 minutes.

Although the frequency of solar eclipses is not considerably different from that of lunar eclipses, they are rarely seen because they are visible only along an extremely narrow path of the Earth. During a solar eclipse, the Moon obstructs the Sun and casts its shadow on the Earth. However, because the Moon is relatively small, the shadow cast during totality never exceeds 270 kilometres in width. If the observer is located in only a portion of the shadow (the penumbra), they would observe a partial solar eclipse where the Moon would only partially cover the Sun. Despite being partially obscured, the Sun is still so bright it would appear no different to the unaided eye (never look directly at the Sun, even during a solar eclipse). It is not until the observer is located within the central region of the Moon’s shadow (the umbra) that the Sun becomes completely covered. Totality of a solar eclipse lasts at most about seven and a half minutes, at which time only the Sun’s corona is visible and several stars will be visible in the daytime sky. Because a solar eclipse can only occur when the Sun and Moon are in the same region of the sky, it can only take place during the new moon phase.

In addition to the partial and total eclipses, there is a third type of solar eclipse called the annular eclipse. The annular eclipse can only occur when the Moon is near apogee (its furthest distance from the Earth). At this time, the Moon appears fractionally smaller in size than usual and is therefore not large enough to fully cover the Sun. During an annular eclipse, the observer would see a bright golden arc or a full ring of light around the darkened Moon.