What this is

A first-person view of the sky as it would look standing on the Moon, at any date you choose. Nothing here is decorative: the Sun and Moon come from Meeus's Astronomical Algorithms, the librations place your feet on the real lunar surface, and the planets come from JPL's orbital elements.

Three things that surprise people

• A day lasts a month. Sunrise to sunset is about 14.8 Earth days.
• Earth never moves. It hangs in one patch of sky forever, turning on its axis and cycling through phases — the Moon is tidally locked, so Earth never rises or sets the way the Sun does. On the far side you never see it at all, and right on the limb libration alone can lift it in and out of view.
• Earth is bigger than the Sun from here — about 3.7× wider. The sky stays black at noon, because there is no air to scatter the light.

Controls

Drag to look around, pinch or scroll to zoom. The speed row runs from real time to a week a second. The dial in the corner is a sky map — zenith at the centre, horizon at the rim; tap it to look that way.

Keyboard: space play or pause · ←→↑↓ look around · +− zoom · E face Earth · S face the Sun · N face north · H hide the panels · Esc close this.

Where this came from

Built by Bendigo Games. It runs entirely on your device — no accounts, no analytics, and no network requests once the page has loaded. Add it to your home screen and it works offline, including in aeroplane mode.