Some facts about Sundials

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If you’ve ever visited a historic place, you might have run into a sundial, which is an ancient way to measure local solar time.  A sundial consists of a few different parts, and because there are many makers, they are all different and use slightly different pieces to make the same calculation.

The sundial shown above has a gnomon to tell the time – that is the straight part that sticks up above the disk’s surface.  This is what will cast a shadow and indicate the solar time.  A sundial needs to be aligned with the earth – different dials are aligned in different ways, but generally they will align vertically, horizontally, or with the earth’s axis.

The amount of accuracy is dependent on the maker, as well as the weather – obviously you need at least a little sun to make the dial work.  This is not a clock for after dark!

I hope you’ve enjoyed some facts about sundials.  For more information, see the wikipedia entry.