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Telling The Time From The Stars

Did you ever read Far From The Madding Crowd? Do you recall how Gabriel Oak was able to tell the time from the stars?

Well, telling the time from the stars is quite straight forward as long as you can recognise the Big Dipper and can find Polaris, the North Star.

Imagine a 24 hour clockface centred on Polaris (its a 24 hour clock face as the Earth rotates once every 24 hours) and because of the direction of rotation of the Earth it runs anti-clockwise. Now, at midnight on March 8th each year the pointer stars of the Big Dipper are at the midnight position, vertically above Polaris, the North Star.

There is a slight problem in that this celestial clock runs fast. Because the Earth makes one trip around the Sun in 365 days, and a circle has 360 degrees, the Earth moves ahead about 1 degree in its orbit every day, which in turn, makes the hour hand of our clock move fast anti-clockwise about 1 degree every day. That may sound confusing, but all it really means is that our celestial clock runs about a half hour fast per week, two hours per month.

So, to tell the time by the Big Dipper, face north and imagine our clock face. Find the Big Dipper and draw the imaginary hour hand, from Polaris to the Big Dipper's pointer stars. Figure out what time this reads on our celestial clock, now all compensate for our clock's faster running time. Subtract two hours for each month from March 8th. Subtract 30 minutes for each week, and, if you want to be more accurate, subtract 4 minutes per remaining day. Oh, and don't forget to ADD one hour for British Summer Time. Your answer will be local real time, accurate to within 30 minutes!

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