CHAPTER II.

A HALF-HOUR WITH ORION, LEPUS TAURUS, ETC.


Any of the half-hours here assigned to the constellation-seasons may be
taken first, and the rest in seasonal or cyclic order. The following
introductory remarks are applicable to each:--

If we stand on an open space, on any clear night, we see above us the
celestial dome spangled with stars, apparently fixed in position. But
after a little time it becomes clear that these orbs are slowly shifting
their position. Those near the eastern horizon are rising, those near
the western setting. Careful and continuous observation would show that
the stars are all moving in the same way, precisely, as they would if
they were fixed to the concave surface of a vast hollow sphere, and this
sphere rotated about an axis. This axis, in our latitude, is inclined
about 51-1/2° to the horizon. Of course only one end of this imaginary
axis can be above our horizon. This end lies very near a star which it
will be well for us to become acquainted with at the beginning of our
operations. It lies almost exactly towards the north, and is raised from
50° to 53° (according to the season and hour) above the horizon. There
is an easy method of finding it.

We must first find the Greater Bear. It will be seen from Plate 1, that
on a spring evening the seven conspicuous stars of this constellation
are to be looked for towards the north-east, about half way between the
horizon and the point overhead (or _zenith_), the length of the set of
stars being vertical. On a summer's evening the Great Bear is nearly