Wednesday, December 23, 2009

Tarwathielemma

Stuart, FL
No LL

Yesterday I explained a little about analemmas. I also said that I wanted to make one for Tarwathie. Here are my results.

Above is a standard analemma illustrating the classic figure-8 shape.

Above is a tutulemma (an analemma in which one of the sun exposures shows a total eclipse) Credit & Copyright: Cenk E. Tezel and Tunç Tezel (TWAN)

Above is a Tarwathielemma. The yellow line shows the actual position of the sun seen from the deck of Tarwathie throughout the year 2009. It is not a figure-8 because Tarwathie's position on the globe changes. For comparison, the dashed line shows a standard analemma as seen from Oriental, North Carolina.

In order to completely track the sun and squash the Tarwathielemma flat, we would have to travel 46 degrees of latitude each way. We actually travel only 20 degrees. Therefore, the Tarwathielemma is truncated.

Above are 2 Ammeleihtawrats (Tarwathielemma spelled backwards, plural.) It doesn't show the sun. Rather, it shows the locus of our travels for the past two years. The red line is 2008 (when we went to Maine for the summer) and the green line is 2009 (when we went to Vermont for the summer.)

Interestingly, even though the Tarwathilemma is truncated, our yearly locus is roughly figure-8 in shape. The center of the figure-8 is Oriental, North Carolina. Remarkably, our log book shows that despite traveling with no plans, we hit Oriental on the same calendar days each spring and each fall for the past 2 years.

Now, ain't that cool?

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