Boötes is one of the largest and finest of the northern
constellations. It can be easily distinguished by its peculiar
kite-shaped grouping of stars or by the conspicuous pentagon
(five-sided figure) of stars which it contains. The most southerly
star in this pentagon is known as Epsilon Boötes and is one of
the finest double stars in the heavens. The two stars of which it
consists are respectively orange and greenish-blue in color.
By far the finest object in Boötes, however, is the magnificent
Arcturus, which is the brightest star in the northern hemisphere
of the heavens. This star will be conspicuous in the evening hours
throughout the summer months, as will also the less brilliant Spica
in Virgo.
Some recent measurements show that Arcturus is one of our nearer
neighbors among the stars. Its distance is now estimated to be about
twenty-one light-years. That is, a ray of light from this star takes
twenty-one years to reach the earth, traveling at the rate of one
hundred and eighty-six thousand miles per second. It would seem as
if we should hardly speak of Arcturus, twenty-one light-years away,
as a near neighbor, yet there are millions of stars that are far
more distant from the earth, and very few that are nearer to us than
Arcturus.
The brightness of Arcturus is estimated to be about forty times that
of the sun. That is, if the two bodies were side by side, Arcturus
would give forth forty times as much light and heat as the sun.
Arcturus is also one of the most rapidly moving stars in the heavens.
In the past sixteen centuries it has traveled so far as to have
changed its position among the other stars by as much as the apparent
width of the moon. Most of the stars, in spite of their motions
through the heavens in various directions, appear today in the same
relative positions in which they were several thousand years ago. It
is for this reason that the constellations of the Egyptians and of
the Greeks and Romans are the same constellations that we see in the
heavens today. Were all the stars as rapidly moving as Arcturus, the
distinctive forms of the constellations would be preserved for only a
very few centuries.
[Illustration: JUNE--VIRGO]
Virgo, which lies south and southwest of Boötes, is a large,
straggling constellation, consisting of a Y-shaped configuration of
rather inconspicuous stars. It lies in the path of our sun, moon and
planets, and so is one of the zodiacal constellations. The cross in
the diagram indicates the present position of the autumnal equinox,
the point where the sun crosses the equator going south, and the
position the sun now occupies at the beginning of fall.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account