New in Wolfram Mathematica 7: Dynamic Astronomical Computation  previous | next 
Compute Position-Dependent Analemmas
Determine the value of a number of properties that vary with observer location. Plotting the altitude and azimuth of the Sun for the same time throughout the year results in a pattern known as the analemma.
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Click for copyable input
positions = Table[{

    AstronomicalData[

     "Sun", {"Azimuth", {2008, 1, i, 8.5}, {40.1, -88.2}}, 

     TimeZone -> -5], 

    AstronomicalData[

     "Sun", {"Altitude", {2008, 1, i, 8.5}, {40.1, -88.2}}, 

     TimeZone -> -5]}, {i, 1, 365.25, 5}];

Graphics[{Orange, PointSize[.03], Point[positions]}, Frame -> True, 

 FrameLabel -> {"azimuth", "altitude"}]
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