Earth's shadow can be divided into two exclusive parts: the umbra and penumbra. Earth absolutely occludes direct solar radiation inside the umbra, the central region of the shadow. However, due to the fact that the Sun's diameter appears about one-quarter of Earth's in the lunar sky, the planet only partially blocks direct daylight within the penumbra, the outer component of the shadow.
A penumbral lunar eclipse happens when the Moon passes via Earth's penumbra. The penumbra causes a refined dimming of the lunar surface. A special type of penumbral eclipse is a complete penumbral lunar eclipse, throughout which the Moon lies completely inside Earth's penumbra. Total penumbral eclipses are rare, and when these occur, the portion of the Moon closest to the umbra may also show up barely darker than the rest of the lunar disk.
A partial lunar eclipse takes place when only a portion of the Moon enters Earth's umbra, whilst a whole lunar eclipse takes place when the entire Moon enters the planet's umbra. The Moon's average orbital speed is about 1.03 km/s (2,300 mph), or a little more than its diameter per hour, so totality may additionally final up to almost 107 minutes. Nevertheless, the complete time between the first and the last contacts of the Moon's limb with Earth's shadow is tons longer and could last up to four hours.
The relative distance of the Moon from Earth at the time of an eclipse can have an effect on the eclipse duration. In particular, when the Moon is near apogee, the farthest point from Earth in its orbit, its orbital velocity is the slowest. The diameter of Earth's umbra does not reduce extensively within the modifications in the Moon's orbital distance. Thus, the concurrence of a definitely eclipsed Moon near apogee will extend the duration of totality.
A central lunar eclipse is a total lunar eclipse for the duration of which the Moon passes through the centre of Earth's shadow, contacting the antisolar point. This type of lunar eclipse is incredibly rare.
