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| My Backyard at the End of the Day |
This is a great experiment that you can take advantage of a really cold day in Vancouver. At the end of the day there will still be frost on the grass where the Sun didn't managed to reach throughout the day. Because my back fence runs from east to west, this line of frost marks the highest point that the Sun reached in the sky during the day. My back fence is five feet tall and the frost line lies fifteen feet from the fence, meaning that the Sun reached an altitude of arctan(5/15) or 18 degrees during that day.
This means that the declination of the Sun was 49-(90-18) = -23 around the end of 2010 which is about right. It's amazing what you can figure out with a bit of frost.
