Vega (Arabic for "Falling Eagle") is the resplendent, bluish-white,
first-magnitude star that lies in the constellation of Lyra, The Lyre
or Harp, a small, but important, constellation just east of Hercules
and a little to the southeast of the head of Draco. Vega is almost
exactly equal in brightness to Arcturus, the orange-colored star in
Boötes, now lying west of the meridian in the early evening hours.
It is also a near neighbor of the solar system, its light taking
something like forty years to travel to the earth. Vega is carried
nearly through the zenith of Washington and all places in the same
latitude by the apparent daily rotation of the heavens. It is a star
that we have no difficulty in recognizing, owing to the presence of
two nearby stars that form, with it, a small equal-sided triangle
with sides only two degrees in extent. If our own sun were at the
distance of Vega, it would not appear as bright as one of these faint
stars, so much more brilliant is this magnificent sun than our own.
The two faint stars that follow so closely after Vega and form the
little triangle with it are also of particular interest. Epsilon
Lyræ, which is the northern one of these two stars, may be used as a
test of keen eyesight. It is the finest example in the heavens of a
quadruple star--that is, "a double-double star." A keen eye can just
separate this star into two without a telescope, and with the aid of
a telescope, each of the two splits up into two stars, making four
stars in place of the one visible to the average eye. Zeta, the other
of the two stars that form the little triangle with Vega, is also a
fine double star. The star that lies almost in a straight line with
Epsilon and Zeta and a short distance to the south of them is a very
interesting variable star known as Beta Lyræ. Its brightness changes
very considerably in a period of twelve days and twenty-two hours.
This change of brightness is due to the presence of a companion
star. The two stars are in mutual revolution, and their motion is
viewed at such an angle from the earth that, in each revolution, one
star is eclipsed by the other, producing a variation in the amount
of light that reaches our eyes. By comparing this star from day to
day with the star just a short distance to the southeast of it, which
does not vary in brightness, we can observe for ourselves this change
in the light of Beta Lyræ. There are a number of stars in the heavens
that vary in brightness in the same manner as Beta Lyræ, and they are
called eclipsing-variable stars.
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