Final answer:
The moon appears rusty red during a total eclipse due to light scattering in the atmosphere.
Step-by-step explanation:
The moon appears rusty red when it is totally eclipsed because of the phenomenon called light scattering in the atmosphere. When sunlight passes through the Earth's atmosphere, it gets scattered. Blue light scatters more easily than red light due to its shorter wavelength. However, during a total lunar eclipse, only red light from the Sun's rays is able to reach and illuminate the Moon, creating a reddish glow.