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    Results of a equal altitude exercise
    From: John Huth
    Date: 2011 Nov 5, 12:18 -0400


    I gave my students the exercise of plotting the altitude of the sun versus time.   They used a setup that had a straw taped to the end of a protractor and a line hanging down to a plumb bob.    The altitude was found by imaging the shadow of the straw on a piece of paper.


    They also looked at the azimuth of the sun versus time by dropping a horizontal using a plumb bob and they had to track this versus time as well.

    They got latitude and longitude first by a graphical method, and then fit a parabola to the curve.   In my own attempt at this, I took 18 sights. 

    The fit for latitude gave me my latitude to within 5 nm, for longitude, the fit gave me something to within 10 nm.   I consider that rather remarkable, but I took some pains to damp the plumb bob by letting it hang into a jar of water, and used a very fine fishing line.

    The students, well, some interesting results.   Most did the bare minimum of measurements.  Their results were sometimes approximately correct, however, some got longitudes larger than 180 degrees.   Some got latitudes as small as 9 degrees.  We're at 42 deg N in Boston.

    One guy got latitude and longitude precise to less than an arc-minute, and I flagged this guy for my TF's to scrutinize.  I think he may have used a sextant, however.


       
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