An astronaut on the surface of the Moon would see a black sky, even during the day. Here's why:

* No Atmosphere: The Moon has practically no atmosphere. Unlike Earth, where the atmosphere scatters sunlight, creating a blue sky, the Moon's vacuum doesn't scatter light.

* Direct Sunlight: Without an atmosphere, the sunlight reaching the Moon's surface is not scattered. Therefore, you see the black void of space directly.

* Stars: The absence of atmosphere also means there's no light pollution, allowing astronauts to see stars incredibly vividly, even during the "daytime" on the Moon.

So, while the Sun might be shining brightly, the sky above would appear as a deep, inky black.