Animation of the lunar eclipseDuring an eclipse (even a full one), the moon does not disappear completely, but turns dark red. This is due to the fact that the Moon, even in the phase of a total eclipse, continues to be illuminated. The sun's rays passing tangentially to the Earth's surface are scattered in the Earth's atmosphere and due to this scattering partially reach the Moon.
Since the earth's atmosphere is most transparent to the rays of the red-orange part of the spectrum, it is these rays that reach the surface of the Moon to a greater extent during an eclipse, which explains the color of the lunar disk. In fact, this is the same effect as the orange-red glow of the sky at the horizon (dawn) before sunrise or immediately after sunset.
Dark Space
