An astronaut on the Moon facing Earth during an eclipse would observe a solar eclipse.

Here's why:

* Solar eclipses occur when the Moon passes between the Sun and Earth, blocking the Sun's light from reaching Earth.

* From the Moon's perspective, the Earth would be positioned between the Moon and the Sun during this time.

* The astronaut would see the Earth completely blocking the Sun, creating a total solar eclipse.

Let me know if you'd like to know more about solar eclipses!