The morning news. [volume] (Savannah, Ga.) 1887-1900, 1896-06-07
THE HIGH SCHOOL TELESCOPE
THE GRADUATING CLASS GIFT To
THE SCHOOL.

Il Is Expected 10 Arrive From the
Makers This Week-The Achieve
ments of the Telescope In Science.
The First Telescope Made in 1910.
The Discoveries by the Great Tel
escopes of the World.
The High School telescope ordered from
Alvin Clark & Sons is expected 10 arrive
this week. 1t is a gift from the gradual
ing class OF IS 10 the High School, and will
be the largest telescope in the state.
IT was purchased with a fund raised by
the members Of the graduating class by
subscription and by the contributions of
trends. As soon as 1t arrives, IL will be
mounted, and will become a part of the
property Of the High School. Mr.. Otis
Ashmore OF the scientific department has
taken a good deal Of interest in Sc
curing the telescope. It VIII be tenn
porarily mounted IN the school yard,
where observations Will be made until the
instrument is permanently mounted. The
telescope has a six-inch lens and was
selected chiefly for its superior optical
properties.
From time to time one reads Of the
wonderful revelations Of the worlds great
telescopes, and, while comparatively few
persons ever nave an opportunity OF look
ing through lleIn. all nave a curious IN
tereSt IN the instruments themselves and
IN what they reveal Of the great creation
around US. The first telescope, invented
by Gallileo in 1910. was constructed upon
the plan of our modern opera glass eX-
ceDt that it was single-barreled. and
magnifed only about thirty diameters. 1t
was a very crude instrument, with piece
of lead pipe for tube, yet by II the
moons of Jupiter were discovered, the
irregularities upon the moons surface
We're shown to be mountains, Venus by
its crescent shape was shown to be nom
luminous, and to revolve around the sun,
and the old Ptolemaic theory, which for
fourteen hundred years had taught that
the earth was nXed and that the sun,
moon and stars revOlved around it, was
exploded and the present theory OF Co
pernicus established. The history Of the
telescope shows, curiously enough, that
II was first used for purposes of war.
There are two classes of telescopes, the
rejecting and the refracting, each of
which possesses merits of its own SUI
perior 10 those of the other.
The rejecting telescope consists Of a
large cOncaVe mirror of Speculum metal,
an alloy of tin and copper placed in
hollow tube. This mirror forms an inn
age of the object to be observed, and
it is magnifed by the eye-piece in the
ordinary way. The advantages of this
form of telescope are its cheapness and
ease of construction and their perfect
achromatism, that is their freedom from
resolving the light into its seven colors,
as is the case with refracting telescopes.
This last advantage is unQuestiOnably
very great one, especially in photogra-
ply and in spectroscopic work. But re-
fecting telescopes are heavy and unwiel-
dy their mirrors need frequent repolish.
ing which is a very delicate piece Of
work, and, in the case of large instru
ments, the weight Of the mirror itself
produces, in spite Of all that can be
done, a slight bending Of the mirror,
and such a consequent distortion of the
image as to render the larger forms of
the instrument almost useless. The larg-
est rejecting telescope ever made was
that of Lord Rose, which was six feet
in diameter but the best results ever
obtained with this class of instrument
have been with mirrors Of much less di-
ameter The smallest satellite of Saturn
was discovered by Herschel with a four
foot speculum, but all the other satellites
discovered by him were seen with an IS
inch mirror.
The refracting telescope is the kind now
used almost exclusively. While il is sub
ject to many difficulties in the quality of
the glass employed for the lenses, in cor
recttng the chromatic and spherical aber-
ration, and in grinding the lenses accu-
rately to the required curves, yet the skill