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The data table has been filled out with the computed altitude for the
Sun at each time interval. Follow the example for the calculation part
to see how I arrived at the computed altitudes.
(11:30AM) 10cm/9.1cm = 1.0989, then hit INV TAN or SHIFT TAN and the result will be 47.69 degrees. Pretty straight forward math. Be careful how you enter the data correctly. The gnomon height divided by the shadow length equals the tangent of the altitude. Then INV TAN equals the altitude.
If you look at this data table you will notice that on the the date I took the data we were nearing the Spring Equinox, so the altitude was nearing 60 degrees. Remember that to find the altitude of the celestial equator, you take 90 degrees minus your latitude. For Huntsville it is 90-30 equals 60 degrees. Do you see the correlation in the data table?
Now that your data is complete, go ahead and plot your results on a
piece of graph paper. Do your altitude plot on the "y"
axis and time plot on your "x" axis. For the
time being, stop right here and bring your graph, data table and gnomon
board in for me to look at.