# The Moon

Also called: Moon, lunar.

Earth's only natural satellite, 3,474 km across and about 384,000 km away — the easiest telescope target of all.

The Moon goes round the Earth once a month, showing us the same face. Its [phase](https://astropilot.space/glossary/phase) changes as we see more or less of its sunlit side; the best detail is along the [terminator](https://astropilot.space/glossary/terminator), where shadows are long.

Its light is the biggest enemy of deep-sky observing: from about first quarter to last quarter, moonlight brightens the sky and hides faint [galaxies](https://astropilot.space/glossary/galaxy) and [nebulae](https://astropilot.space/glossary/nebula). Planets, double stars and the Moon itself don't mind.

**At the eyepiece:** Never look at the full Moon at high power without a [moon filter](https://astropilot.space/glossary/moon-filter) if it dazzles you — and enjoy the crescent and quarter phases most.

**In AstroPilot:** Tonight shows the Moon's phase, rise and set, and how much it brightens the sky; every rating accounts for moonlight.

**Examples:** [moon](https://astropilot.space/object/moon.md)

**Related:** [Phase](https://astropilot.space/glossary/phase.md), [Terminator](https://astropilot.space/glossary/terminator.md), [Mare](https://astropilot.space/glossary/mare.md), [Crater](https://astropilot.space/glossary/crater.md), [Libration](https://astropilot.space/glossary/libration.md), [Earthshine](https://astropilot.space/glossary/earthshine.md), [Moonlight](https://astropilot.space/glossary/moonlight.md)

From the AstroPilot astronomy glossary: https://astropilot.space/glossary/the-moon