The Jasper weekly courier. [volume] (Jasper, Ind.) 1858-1922, 1915-07-16

How Astronome-s SCI About the Task
81 Measuring Il.
With the exception Of a hundred
stars At most, We know nothing OF
the distances of the individual stars
What T. the cause of this state 81
things? 1t Is owing 70 the fact that
we have two eyes that we are en-
abied not only to perceive the di-
, rechon in which external objects
ere. Situated, bat to get an idea Of
their Distance, 20 locshze them in
space. Bnt this power is rather lin
tied. Fer distances exceeding some
hundreds Of yards IL utterly fails
The reason IS that the distance be-
tween the eyes as compared with
/ the distance TO be evaluated be
comes too small. Instruments have
been devised by which the distance
between the eyes is. as it were, ark-
fcially increased. With a good IN
rtrument OF thLSWsort distances OF
several miles ms~be eyaluated. For
still greater distances we may inn
Sgine each eye replaced BY photo
graphic plate! Even this would be
quite sufficient for one Of the heav-
enlv boz es-.viz, for the moon.
At ono andst,e same moment let
a photograph .the moon and the
surrounding stars be taken both at
the Cape observatory and at the
Royal observatory at Greenwich.
Placing tiie two photographs side By
side in tho stereoscope, wo shall
clearly SEQ fle moon hanging In
space" and may evsluate its dis
tance
But for the Gun and the nearest
planets, our nexs neighbors in the
universe after the moon. the dim-
Guilty Hecommenees--
The reason Is that any available
distance On the earth, taken az eye
distances, Is rather small for the
purpose. However, owing 10 in
credible perseverance, and skill OF
ecvesl observers and by sobstitut
Ing the NEST refined measurement
for stereescopic examination, as
tronorneTs have succeeded In over
coming the difficulty for the sun I
think we may say that at present
We knox its distance 10 within a
Ehousandth part Of its amount.
Knowing the suns distance, we get
HAT Of al the planets by a well
known relation existing between the
planetary distances.
But now for the fixed etars,
which must be hundreds Of thou
sands Of times farther removed than
the gun. There evidently can be no
qnestioD Of any sufficient eye. dis
lance 81 our earth Aeanwhiss eur
success with the sun has provided
Us with a new enc &stancs, e4,OD0
times greater than any possible eye
distance on yAa earth, for now Nnt
ws know &be dk4anoa at which The
earth travels In its oiNi around the
sum We can take tAe diametes Of lbs
orbit az our eye distance. Photo
graphs taken st ysSSOds ok months
spaTt viii represent Che stellar
world .ss seen from poSpts the dis
tRnce between which Is, already best
expressed in the tslo n woutd take
myht 10 trnvoBse it The time would
Sc about sixteen minutes.
However,, even this distance, i'm
nense est Is, IL, on the whole, in
sdequste for obtaining ~ sterso-
scopic view Of the stars. IL IA only
In quite exceptional eases that pho
tographs ON a. Large .eoale-that h,
obtained BY the sid Of big teie-
scogcs~shov any stereoscopie e.
feet FOR fixed starr, BY accurate
measurement Of the photos we may
perhaps get somewhat beyond what
We can attain by simple ytereoscopic
inspection; but, az we said a mo-
R1entago, astronomers have not slrc-
ceoded IN this way In determining
the distance Of more than q hun
bred stars in all.--Scientifc Amssi-
nan 49,