We shall now study the so-called fixed stars, those stars, namely, which
preserve the same relative position and configuration from night to
night, only varying, and that with perfect regularity, in the times at
which they reach the meridian. For this reason they have been known from
the dawn of astronomy as fixed stars, in contrast with the planets or
wandering stars.
The observer who watches the nightly changes in the sky with close
attention will soon perceive that all these fixed stars appear to move
in circles or parts of circles. Some of them describe larger circles
than others, and the further south a star is when it passes the
meridian, the larger circle will it describe.
It cannot be too often repeated that this motion of the stars is only
apparent, being due to the real rotation of the earth, along with the
observer on its surface, in the contrary direction. It is estimated that
there are about three thousand stars visible to the naked eye in our
latitude, though not all these are visible at the same time, many of
them being below the horizon, while others are elevated in the sky at
different times and seasons.