, 93, 94.]

[Footnote 14: A catalogue of radial velocities has this year been
published by J. VOUTE, embracing 2071 stars. "First catalogue of radial
velocities", by J. VOUTE. Weltevreden, 1920.]

CHAPTER III.

SOME GROUPS OF KNOWN STARS.

29. The number of cases in which all the eight attributes of the stars
discussed in the first chapter are well known for one star is very
small, and certainly does not exceed one hundred. These cases refer
principally to such stars as are characterized either by great
brilliancy or by a great proper motion. The principal reason why these
stars are better known than others is that they lie rather near our
solar system. Before passing on to consider the stars from more general
statistical points of view, it may therefore be of interest first to
make ourselves familiar with these well-known stars, strongly
emphasizing, however, the exceptional character of these stars, and
carefully avoiding any generalization from the attributes we shall here
find.

30. _The apparently brightest stars._ We begin with these objects so
well known to every lover of the stellar sky. The following table
contains all stars the apparent visual magnitude of which is brighter
than 1m.5.

The first column gives the current number, the second the name, the
third the equatorial designation ([alpha][delta]). It should be
remembered that the first four figures give the hour and minutes in
right ascension, the last two the declination, italics showing negative
declination. The fourth column gives the galactic square, the fifth and
sixth columns the galactic longitude and latitude. The seventh and
eighth columns give the annual parallax and the corresponding distance
expressed in siriometers. The ninth column gives the proper motion
([mu]), the tenth the radial velocity _W_ expressed in sir./st. (To get
km./sec. we may multiply by 4.7375). The eleventh column gives the
apparent visual magnitude, the twelfth column the absolute magnitude
(_M_), computed from _m_ with the help of _r_. The 13th column gives the
type of spectrum (_Sp_), and the last column the photographic magnitude
(_m'_). The difference between _m'_ and _m_ gives the colour-index
(_c_).

TABLE 2.

_THE APPARENTLY BRIGHTEST STARS._

[Transcriber's Note: To conserve space (ad) is used in place of
([alpha][delta]).]

+--+---------------------+----------+--------+-----+-------+-------+-------+
| 1| 2 | 3 |