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\@writefile{toc}{\contentsline {section}{\numberline {1.1}Introduction}{1}}
\@writefile{toc}{\contentsline {section}{\numberline {1.2}The Seasons}{2}}
\@writefile{lot}{\contentsline {table}{\numberline {1.1}{\ignorespaces {\bf  Season Data for Select Cities}}}{2}}
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\@writefile{lof}{\contentsline {figure}{\numberline {1.1}{\ignorespaces An ellipse with the two ``foci'' identified. The Sun sits at one focus, while the other focus is empty. The Earth follows an elliptical orbit around the Sun, but not nearly as exagerrated as that shown here!}}{3}}
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\@writefile{lof}{\contentsline {figure}{\numberline {1.2}{\ignorespaces Pointing a camera to the North Star (Polaris, the bright dot near the center) and exposing for about one hour, the stars appear to move in little arcs. The center of rotation is called the ``North Celestial Pole", and Polaris is very close to this position. The dotted/dashed trails in this photograph are the blinking lights of airplanes that passed through the sky during the exposure.}}{9}}
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\@writefile{lof}{\contentsline {figure}{\numberline {1.3}{\ignorespaces Here is a composite of many different exposures (each about in one hour in length) of the night sky over Vienna, Austria taken throughout the year (all four seasons). The images have been composited using a software package like Photoshop to demonstrate what would be possible if it stayed dark for 24 hrs, and you could actually obtain a 24 hour exposure (which can only be truly done north of the Arctic circle). Polaris is the ``C''-shaped arc at the very center.}}{10}}
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\@writefile{lof}{\contentsline {figure}{\numberline {1.4}{\ignorespaces The Earth's spin axis always points to one spot in the sky, {\it  and} it is tilted by 23.5$^{\rm  o}$ to its orbit. Thus, as the Earth orbits the Sun, the illumination changes with latitude: sometimes the North Pole is bathed in 24 hours of daylight, and sometimes in 24 hours of night. The exact opposite is occuring in the Southern Hemisphere.}}{14}}
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\@writefile{toc}{\contentsline {section}{\numberline {1.4}Elevation Angle and the Concentration of Sunlight}{14}}
\@writefile{lof}{\contentsline {figure}{\numberline {1.5}{\ignorespaces Altitude (``Alt'') is simply the angle between the horizon, and an object in the sky. The smallest this angle can be is 0$^{\circ }$, and the maximum altitude angle is 90$^{\circ }$. Altitude is interchangebly known as elevation.}}{15}}
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\@writefile{lof}{\contentsline {figure}{\numberline {1.6}{\ignorespaces An ellipse with the major and minor axes defined.}}{16}}
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\@writefile{lof}{\contentsline {figure}{\numberline {1.7}{\ignorespaces The Celestial Equator is the circle in the sky that is straight overhead (``the zenith'') of the Earth's equator. In addition, there is a ``North Celestial'' pole that is the projection of the Earth's North Pole into space (that almost points to Polaris). But the Earth's spin axis is tilted by 23.5$^{\circ }$ to its orbit, and the Sun appears to move above and below the Celestial Equator over the course of a year. }}{18}}
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\@writefile{toc}{\contentsline {section}{\numberline {1.5}Summary {\it  (35 points)}}{19}}
\@writefile{toc}{\contentsline {section}{\numberline {1.6}Extra Credit}{19}}
\@writefile{toc}{\contentsline {section}{\numberline {1.7}Possible Quiz Questions}{19}}