Stonehenge and seasons
- At vernal equinox
- Sun on equator -- rises exactly East f. 2-16
- Thereafter moves N -- furthest N June 22 (summer solstice)
- meaning of solstice -- sun stands still
- Sun turns around, and heads back South
Therefore Stonehenge could determine Seasons
- Mark celebrations of summer
- prepare for Winter (food, clothing shelter)
Counting days wouldn’t work
- year is 365.2503 d long
- not an even number. If 365 were used
- off by 25 d after 100 y, not good enough
What if cloudy at Summer solstice?
- Not to worry, measure sunrise before and after -- interpolate