Moon Clock
Tonight's sky, on your desk
How to read it
Point at a step, or tap it, to light up that part of the clock.
-
The bright area shows the Moon as it looks tonight.
Right now
-
Northern hemisphere: as it waxes, the right side lights up first; as it wanes, only the left side stays lit.
Right now
-
A full cycle takes 29.5 days.
Right now
-
The label shows the lunar age in days and the lit percentage.
Right now
The story
Moon dials appeared on European longcase clocks in the 17th century so travelers and evening visitors could plan around moonlight. This one computes the real phase for today.
- Year
- 17th century
- Place
- Europe
- Creator
- European clockmakers
Fun fact
The synodic month is 29.53 days — that awkward fraction is why antique moon dials drifted and needed manual correction.
