Moon Phase Software

Moon tools and calendars

Export and integrate
Observe the Moon
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Personal dates and calendars
Explore lunar geometry

Moonlight calculator

Estimated horizontal moonlight at 18 October 2026 at 21:00 UTC: 0.0005 lux.

Enter your observing coordinates; north and east are positive. Search a city and its local sky path.

Default: UTC. Choose a named zone for local dates.
Moon elevation used by model
6.02°
Illuminated lunar disc
52.03%
Air extinction
0.2 magnitudes per airmass
Observer range
401557.0 km

The estimate uses 0.267 lux for a full Moon at 384,400 km overhead before extinction, scales with inverse-square distance, lunar phase darkening and the sine of altitude, and dims by the chosen extinction. It describes horizontal illumination under clear air, without cloud or terrain.