How to set the moon dial (the moon's age)
on your clock

A moon dial indicating the moon's age
as about 13/14 days.
Click here for the moon's age today
(and a lot more moon stuff)

The moon's age will appear
under the moon's image.
like this:
Moon's Age (days past new moon)

You may be able to move the dial
using your fingers (clockwise only),
but it is often necessary to remove
the hood or side panels to get to
the back of the disk.

The moon dial isn't always at
the top, and with older clocks,
it's always a good idea to
work from the back.

Here's how things look from behind
on a modern clock:

Moon Disk
A moon disk
(and some small print)

A moon disk has 59 teeth and is indexed twice in 24 hours. It makes half a revolution in 29-1/2 days. The moon actually circles the earth in a sidereal month averaging 27 days, 7 hours, 43.2 minutes. However, because the Earth is constantly moving along its orbit about the Sun, the Moon must travel slightly more than 360° to get from one new moon to the next. Thus, the lunar month is longer than the sidereal month, lasting 29 days, 12 hours, and 44.05 minutes, not exactly the 29-1/2 days measured by your moon dial - but close !!

Here's this month's moon phase calendar
   - is your moondial set properly?