Analemma calendars are a common feature at science museums and planetariums. They exploit the fact that the sun travels in a predictable pattern over the course of a year and trace the projection of an object's shadow to measure time (weeks and months).
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Analemma — was also a book by Ptolemy .In astronomy, an analemma (IPA: IPA|/ˌænəˈlɛmə/, Latin for the pedestal of a sundial) is a curve representing the angular offset of a celestial body (usually the Sun) from its mean position on the celestial sphere as… … Wikipedia
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