Using a sundial was a way to tell local time during the day, but what about at night? Answer: The Moon clock. If you study the phase and position of the moon, you begin to recognize a pattern between the Moons rising, setting, highest position in the sky, and local time. You do not need to know the phase, but adding that to this clock would make it more educational. To use this clock, you simply need to go outside, place the Moon in the window that is most close to the current shape of the moon, while keeping the base level. The current time can then be estimated with a reasonable degree of accuracy. This is a basic model and can be scaled to fit your size requirements, however, the text may be unreadable at very small scales. You may also find that this is great for telling time during the day as well. As long as you are facing South, position the New Phase Moon (the one with the filled circle) in the general position of the sun (never look at the sun) It will give you a fair estimate of the local time