"RichD" wrote in message ...
When and how did astronomers determine that the earth's axis
tilts from the ecliptic, and its value?

--
Rich


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You can do it yourself, find a large rock or boulder or standing stone
and mark the ground where the tip of the shadow falls. Do that
throughout the year and your sundial becomes an astrolabe.
http://danny.oz.au/travel/scotland/p...g-stenness.jpg
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