Stronger atmospheric scattering of blue light means that the light that reaches the lunar surface is predominantly red in colour, so for observers on Earth the eclipsed part of the Moon may be brick-coloured, rusty, blood red, or sometimes dark grey, depending on terrestrial conditions. The Moon is full, moves into the shadow of the Earth and dims dramatically but usually remains visible, lit by sunlight that passes through the Earth’s atmosphere. In a lunar eclipse, the Earth, Sun, and Moon are almost exactly in line and the Moon is on the opposite side of the Earth from the Sun.
