Vilas County news. [volume] (Eagle River, Vilas County, Wis.) 1896-1927, 1903-11-23
ONE AT CAMBRIDGE AND ONE IN
SOUTH AMERICA.
OF THE REJECTING TYPE
Modern Astronomical Science Turns
Back a Century for a Model
Two Years of Hard Labor on a
Single Mirror.-other Matters of
Interest.

CeSSIQl mas DCGH inc pA SAAAAAAaAg WIN
with the new 24-inch Clark mirror
for the Harvard observatory, that a
! second and similar telescope has been
? ordered. One of these instruments
will be set up at Cambridge or at
\ some other point near Boston, while
the other will go to the Harvard sta
ton at Arequipa, Peru. there to take
it's part in the systematic study and
Photographic record of the southern
4 frmament-a work which parallels
and completes the labOrs of the Cam
I, bridge observatory.
The new Arequipa telescope is in
/ teresting. moreover, because it is go
\ ing to give a practical opportunity
! to test side by side two telescopes of
opposite character. For many years,
it may be recalled, there have been
controversies among astronomers re-
garding the respective merits of re-
| fracting and rejecting telescopes. A
refracting telescope is similar to the
I layman's spyglass in constructions
long tube with convex lens, at one
end and an eye-piece at the other
J so that you look right through it di-
| rectly at the stars. On the other
hand, a rejecting telescope, such as
Harvard's mirror is made for. reverses
the order of things, so to speak, for
the observer gets up at the elevated
end and looks down into a cOncave
mirror across the face of which the
/ heavenly bodies swim in their mag
nified form. The new Harvard tele-
scope will be of the rejecting type,
having n mirror of carefully polished
glass backed with silver. When it is
finished it will be set at Arequipa side
by side with a refracting telescope of
the same size and operated under the
same general conditions. In such
circumstances 9 comparison may
easily be made which, it is believed,
will do more than merely satisfy
scientific curiosity, since it will re-
veal definitely the respective value of
these two important types of modern
telescopes in certain difficult fields
of astronomical research.
During the past 10 or 20 years
there has been, it is said, a decided
reaction among astronomers in
favor of the type of instrument just
ordered by the Harvard observatory
and honored, even by those who
supported the claims of its refracting
rival, as the instrument used by the
Herschels in making some of the
greatest discoveries of modern as
tronomy. True it is that after Lord
Ross had his giant telescope made,
/ the refracting type came into very
general use, since the instrument is
much easier to handle. There is an
objection, however, in that one has to
pay for this greater convenience by a
| loss of much Of the light transmitted
| through the refracting lenses. Some
/ 20 years ago Mr.. Common, an English
astronomer, once more attracted at
| tention to the rejecting telescope by
the admirable results which he OBJ
tanned. Later a still larger reflector
was made in England, but nothing
much was done with it until t passed
into the hands of Professor Keller,
| of the Lick Observatory, who used it
while making additions TO our knowl-
edge of the patches of distant stars
| known as nebulae. This work was
continued after Professor Keeler's
death by his successor Professor
| Campbell, and by Mr.. Richey of the
! Yerkes observatory at Lake Geneva,
4 Wis, who himself constructed a large
| reflector with which he included star
/ clusters and double stars as we'll as
, nebulae within the field of his investi-
cations.
/ In the mooted discussion of the
/ value of the two types of instruments
| the work of these astronomers re-
stored the rejecting telescope to a
/ position of great Importance, but
/ proved only, according to some as
trcnomers, that the success lay not in
the instrument itself but in the skill
Of the man who used il. One advan-
7 tage it certainly does have, and a
most important one to the Harvard
: observatory, which has done so much
in photcgraphing stellar spectra-its
focus is unvarying for all colors, while
that of the retracting instrument diff
+ fers considerably.
/ The rejecting telescope, in the
opinion OF these opponents. is a diff
! ficult piece of apparatus to work
+ with, even under the most favorable
| circumstances. The new mirror at
Cambridge. for example-and the mir
ror, Of course, is the first and all i'm
pOrtant consideration in any reflect
! ing telescope-must be mounted In
the most delicate manner, so that it
is a question whether it will finally
be placed at the observatory in Cam
bridge or somewhere else in the neigh
borhood. Electric cars. which though
they help along civilization in gen.
eral. often prove a hindrance to
specific scientific work, pass close by
the observatory and the tremors
started up as they pass as well as