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The Wikipedia article about Orion's belt contains this confusing sentence:

They also mark the northern night sky when the sun is at its lowest point, and were a clear marker for ancient timekeeping.

Is this a reference to the winter solstice? In what sense?

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This was for the approximate timekeeping and you can imagine that it was not as accurate as we would expect at the present. Orion and it's belt rise approximately from the East that time. –  Tigran Khanzadyan Jan 17 '12 at 9:29
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up vote 3 down vote accepted

Orion's Belt is approximately 12 hours away from the winter solstice, so when it is high in the middle of the night, the Sun is at its farthest south. The winter solstice is at 18h 0 m, while Alnilam, the middle star in Orion's Belt, is at 5h 37m.

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Thank you! Would you know where I might find RA values for the winter solstice (I suppose it would still be defined as 18:00) and Alnilam for the centuries before the common era, seeing how the article references ancient timekeeping? I could calculate it in Stellarium but I do not think that is accurate. –  dotancohen Jan 19 '12 at 21:29
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