Evening star. [volume] (Washington, D.C.) 1854-1972, 1907-03-02

clockwork, follows II exactly. The driv-
ing clock Of the great Yerxes telescope
moves a mass of twenty tons with such
precision that the image of the sun will
together. But these ciock-driven tubes Will
not carry great additional weights and the
many instruments which astronomers at
tach to their telescopes for measuring and
photographing the heavenly bodies have not
In the past quarter century been increased
much in power where lens telescopes are
used. But tho new rejecting telescopes
can be so devised that the image can, by
travelling mirrors, be reflected into a sta.
tionary laboratory where the measuring
and Photographic instruments can be given
their full power. thus the little spectre
scopes now attached to lens telescopes can
be increased until forty feet long if needs
be, for attachment to rejecting telescopes.
Another great reflector, sixty inches in
diameter is being constructed for this
Carnegie solar observatory on Mt. Will
son. This has been nearly completed by
Prof. G. w. Ritchey. who will direct the
manufacture of the great 1O0-inch concave
mirror
For Studying Sun Only.
For studying the sun rather than the
stars what is known as the Snow tele-
scope is already stationed upon Mt. Will
son. This, lately purchased from the
Yerkes observatory. is of the reflector c.ass,
although of much less power than the new
telescopes to use the sixty-inch and 100
inch refiectors. With this snow telescope"
daily photographs of the suns image are
now being made on Mt. Wilson. Its long
tube, covered by the white shed seen on
the accompanying photograph, is laid hori-
zontally north and south upon the ground,
and the suns image is reflected into 1t by
a plane mirror driven by clock work. The
mirror is thus the only moving part of the
entire mechanism, and it brings a fixed
image of the sun into a laboratory at the
end of the tube, where it is observed with
large spectrOscopes and other apparatus
mounted on piers.
To Learn Future of Sun.
To learn the past and future of the sun
is the prime function of this new Carnegie
solar observatory. This problem embraces
also the past and future of earth. and all
earthly life, since the sun is the source OF
all earthly life. Those little bright-eyed
sphinxes, the stars and nebulae, hold the
answer to this riddle, and no telescope on
earth can reach one-third near to them
will the enormous instrument to be
equipped with the 100-inch reflector. OF
course, our sun is but star, and all stars
are suns. Many have their planets revolv-
ing about them, in the case of our sun,
but these planets are invisible because, like
earth and its sister planets, they are not
incandescent-not burning. The nebulae
represent the crudest raw material cut of
which the sun was made.
The little three-foot reflector of the
Lick observatory surprised astronomers
by determining at least 100000 of these
luminous, cloud-like patches. the ma
jority of spiral form. How many more
the 100-inch reflector will reveal can only
be guessed at. Suffice 1T to repeat that 1t
will carry the eye three times far in to
the heavenly field as 1t has ever been
carried before. Some astronomers think
that these far-distant nebulae are chang
ing quite perceptibly from generation to