Tell time by the stars!
Sundials are fine during daylight, but what about at night? Here is an accurate, low-tech (and may we add very green) way to tell time by the stars. All you need is a clear night in the Northern hemisphere, the Nocturnal Time Dial is good anytime until the year 2500!
The Nocturnal, or horologium nocturnum, was first used in the 15th century by navigators who needed to tell time by the position of the stars. This particular star dial uses the North Star (Polaris) and your choice of either the Big Dipper or the Little Dipper to determine the hour.
Read our tutorial on telling time with a Nocturnal Time Dial.
The Institute and Museum of the History of Science in Florence, Italy has a very nice introduction to Nocturnal science in English (in Italian).
An overview of the science is included in the detailed instruction booklet. Brief directions for using the Nocturnal Time Dial are on its reverse side.
Nocturnal dimensions: 4¾ inches (12.1 cm) in diameter, excluding the Hour Hand.
The Nocturnal Time Dial is professionally laminated.
Publisher: 4Physics (2008).
Made in the U.S.A.
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