Pleasures of the telescope: An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General ReadersServiss, Garrett Putman
Science
Pleasures of the telescope: An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General Readers
Still retaining the five-inch in use, we may next turn to the other end
of the Belt, where, just under zeta, we perceive the fourth-magnitude
star sigma. He must be a person of indifferent mind who, after looking
with unassisted eyes at the modest glimmering of this little star, can
see it as the telescope reveals it without a thrill of wonder and a cry
of pleasure. The glass, as by a touch of magic, changes it from one into
eight or ten stars. There are two quadruple sets three and a half
minutes of arc apart. The first set exhibits a variety of beautiful
colors. The largest star, of fourth magnitude, is pale gray; the second
in rank, seventh magnitude, distance 42", p. 61 deg., presents a singular
red, "grape-red" Webb calls it; the third, eighth magnitude, distance
12", p. 84 deg., is blue; and the fourth, eleventh magnitude, distance 12",
p. 236 deg., is apparently white. Burnham has doubled the fourth-magnitude
star, distance 0.23". The second group of four stars consists of three
of the eighth to ninth magnitude, arranged in a minute triangle with a
much fainter star near them. Between the two quadruple sets careful
gazing reveals two other very faint stars. While the five-inch gives a
more satisfactory view of this wonderful multiple star than any smaller
telescope can do, the four-inch and even the three-inch would have shown
it to us as a very beautiful object. However we look at them, there is
an appearance of association among these stars, shining with their
contrasted colors and their various degrees of brilliance, which is
significant of the diversity of conditions and circumstances under which
the suns and worlds beyond the solar walk exist.
From sigma let us drop down to see the wonders of Orion's Sword
displayed just beneath. We can use with advantage any one of our three
telescopes; but since we are going to look at a nebula, it is fortunate
that we have a glass so large as five inches aperture. It will reveal
interesting things that escape the smaller instruments, because it
grasps more than one and a half times as much light as the four-inch,
and nearly three times as much as the three-inch; and in dealing with
nebulae a plenty of light is the chief thing to be desired. The middle
star in the Sword is theta, and is surrounded by the celebrated Nebula
of Orion. The telescope shows theta separated into four stars arranged
at the corners of an irregular square, and shining in a black gap in the
nebula. These four stars are collectively named the Trapezium. The
brightest is of the sixth magnitude, the others are of the seventh,
seven and a half, and eighth magnitudes respectively. The radiant mist
about them has a faint greenish tinge, while the four stars, together
with three others at no great distance, which follow a fold of the
nebula like a row of buttons on a coat, always appear to me to show an
extraordinary liveliness of radiance, as if the strange haze served to
set them off.
Public-domain text, read in full here on John Shaqi.
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