The BSS Glossary (courtesy of John Davis) says:
The word analemma has had several other meanings in the history of astronomy and dialling. In the first century BC, the Roman engineer Vitruvius used the word to refer to a graphical construction, equivalent to today's orthographic projection. In the second century AD Ptolemy used analemma to mean an instrument acting as a nomograph for defining the angles of a dial. The use of a modern analemma on a dial dates to around 1640, and the first treatment in English was by Samuel Foster in 1654. Does this help? Patrick -----Original Message----- From: Jack Aubert <jaub...@cpcug.org> To: sundial@uni-koeln.de Sent: Sat, Nov 14, 2009 11:18 pm Subject: Origin of the Analemma figure? I recently revised my notes for a sundial talk I was giving which included a section on the EOT, and its connection with the traditional figure 8 analemma. I wanted to explain its origin, or at least be able to answer the question if asked, but have not been able to find any believable references on how it emerged. I assume that the source of the figure is simply a “connect the dots” picture of what the sun, or a gnomon pointer will trace it out over the course of the year projected onto a surface. But I do not see how the dots can be generated without using an external non-solar source of time. The Wikipedia article on the EOT has a confusing statement to the effect that Ptolomey was aware of the variation in the sun’s movement and even devoted a chapter to the subject, but then says that he did not correctly account for the two sources of variation. Is there any evidence that the Greeks or Romans ware aware of, and used, the analemma representation, perhaps generated by reference to a clepsydra, or did it first appear when mechanical clocks became prevalent? Jack --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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