Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1909-03-09
DISTANCE OF THE STARS.
How Astronomers Set About Meeting
and Measuring 1t.

With the exception of a hundred
stars at most, we know nothing Of the
distances of the individual stars
What is the cause of this state Of
things? 1t is owing to the fact that
we have two eyes that we are enabled
not only to perceive the direction in
which external objects are situated
but to get an idea of their distance, to
localize them in space. But this power
is rather limited. For distances ex-
ceeding some hundreds of yards it
utterly fails. The reason is that the
distance between the eyes as compared
with the distance to be evaluated be-
comes too small. instruments have
been devised by which the distance be-
tween the eyes is. as it were. artl-
ficially increased. With good instru-
ment of this sort distances OF several
miles may be evaluated. For still
greater distances we may imagine each
eye replaced by Photographic plate.
Even this would be quite sufficient Tor
one of the heavenly bodies, viz. for the
moon.
At one and the same moment let
photograph of the moon and the sur
rounding stars be taken both at the
Cape observatory and at the Royal
observatory at Greenwich. Placing
the two photographs side by side IN the
stereoscope, we shall clearly see the
moon hanging in space" and may
evaluate it's distance.
But for the sun and nearest Plan
cts. our next neighbors in the universe
after the moon, the difi1culty recon-
mences. =.
The reason is that any available dis
lance on the earth. taken as eye-dis-
lance. is rather small for the purpose.
However, owing to incredible presever-
ance and skill of several observers, and
by substituting the most rehned
measurement for stereoscopic ex-
animation. astronomers nave sue
ceeded in overcoming the difficulty for
the SUM- / think we may say that dt
present we know its distance to WITHIN
a thousandth part OF Its amount.
Knowing the suns distance. we get
that of all the planets by well known
relation existing between the planetary
distances.
But now for the fixed stars. which
must be hundreds of thousands Oh
times farther removed than the sun.
There evidently can be no question OF
any sufficient eye distance on our earth.
Meanwhile, our success with the sun
has provided us with a new eye-dis-
lance, 24O00 times greater than any
possible eye-distance on the earth, 1or
now that we know the distance at
which the earth travels in its ORBIT
round the sun, we can take the dame
ter of it's orbit as our eye-distance'
Photographs taken at periods SIX
months apart will represent the stellar
world as seen from points the distance
be tween which is already best ex-
pressed in the time it would take ligns
to traverse it. The time would De
about sixteen minutes.
However. even this distance, I'M
mense as it is, is on the whole made
duate for obtaining a stereoscopic
view of the stars. 1t is only in quite
exceptional cases that photographs on
a large scale-that is, obtained by Tue
aid of big telescopes-show any
stereoscopic effect for fixed stars. by
accurate measurement of the photos
we may perhaps get somewhat beyoho
what we can attain by simple stereo-
scopic inspection; but. as we SAID
moment ago, astronomers have not
succeeded in this way in determining
the distance of more than hundreu
stars in all.-Scientific American.