Support

Standing on the Moon

Something broken, confusing, or just worth saying? Email support@bendigogames.com and you will get a reply from a person. It helps to include your device model, your OS version, and the date and landing site you were looking at.

Using it

Does it need an internet connection? No. It makes no network requests at all — everything is computed on your device. It works in aeroplane mode, on a plane, in a tunnel, and years from now if this website is gone.

Nothing I change is remembered. Correct, and deliberate. The app stores nothing on your device, so every launch starts at the current date at Tranquility Base. Set the date and place you want each time; it takes a moment.

Time is not moving. The app opens paused. Tap a speed on the row along the bottom — those are one-tap presets and they start playback themselves. At real time ×1 the sky genuinely barely moves: a lunar day is 29.5 Earth days long, so the Sun crosses the sky at about half a degree an hour. Pick hours or days a second to actually see it.

I hid the interface and cannot get it back. There is a small ▣ button in the top corner that survives hiding everything else; tapping the sky brings the panels back too. If you ever find a state you cannot escape from, that is a bug worth an email.

How do I identify a star? Tap it. The tap target is far larger than the dot, so you do not have to be precise, and when two stars are close the nearer one to your finger wins. Turning on “Constellations & star names” draws the figures as well.

Questions the sky raises

Why is the sky black when the Sun is up? Because there is no air. Daylight on Earth is sunlight scattered by the atmosphere; with no atmosphere to scatter it, the Sun is a fierce light in a black sky, and the stars never go out — your eye simply cannot adapt to both at once.

Why does Earth never rise or set? The Moon is tidally locked, so it turns once on its axis in exactly the time it takes to orbit Earth. From any spot on the near side, Earth hangs in one patch of sky permanently, turning and cycling through phases but never moving from its place. It wanders a little — that is libration, and the wobble trace draws it. From the far side you never see Earth at all.

The Sun looks too small. It is drawn at its true angular size of about half a degree, which is genuinely smaller than Earth as seen from the Moon — Earth is 3.6× wider. It looks small on a screen for the same reason photographs of the full moon disappoint: a screen covers only a narrow slice of your vision. Use Show at life size in the readouts panel to set the zoom so that what you see matches what your eye would.

Is the sun glare real? The glare slider is the one honest exaggeration. At 0 the Sun is drawn at its true size with no halo. Turning it up grows a halo and a fine ciliary corona — the many irregular rays your eye's own lens fibres throw, which is what a person would actually see, rather than the four-pointed cross a camera makes.

How accurate is this? The Sun and Moon come from Meeus's Astronomical Algorithms, the librations place your feet on the real lunar surface, the planets come from JPL's orbital elements, and the star positions and distances are catalogue values. Eclipse predictions reproduce the real eclipse dates. It is accurate enough to plan by and not accurate enough to navigate by.

Privacy

The app collects no data whatsoever, and stores nothing on your device. See the privacy policy.

Last updated: 9 September 2026