To answer this, we need to know which planet you're referring to. Different planets have different moons with varying brightness.

For example:

* Earth: Our Moon is the brightest object in the night sky from Earth's surface.

* Jupiter: Ganymede, Jupiter's largest moon, is actually the brightest moon in the solar system when viewed from Jupiter's surface.

So, tell me which planet you're interested in, and I can tell you which of its moons is the brightest!