The Daily Ardmoreite. [volume] (Ardmore, Okla.) 1893-current, 1914-08-17
MOON A GREAT MYSTERY.
Why Human Eyes Will Never Discern
X Closely,

II Closely.
What are the dimensions, of the
smallest object that could be perceiv-
ed by the human eye, studying the
moon through telescope? Lay
men ask the astronomer this ques-
tion frequently, and it is not so cas-
lily answered as might be supposed.
They ask, How near do the most
powerful telescopes bring us to the
moon? Would we be able to see
human beings if they were walking
around there" The scientific ques-
ton is What is the size of the
smallest object that we could dis.
. .tinguish on the surface of the moon?'
AragO states in his Popular As
tronomy' that as the moon is 23S,-
$50 miles away, telescope magnify
ing is ten times ought to bring it
within $4,000 miles, a magnification of
100 times within 2,3SS miles, and a
magnifcaton of 1000 times to within
23S miles of the earth, so far as
vision is concerned.
What could we see on the moon at
distance of 23S miles? Hardly
anything in detail, for all would be
beyond the power of sight And be.
sides, where is the astronomer who
can hope to obtain a magnitication of
1000 times? The conclusion must be
that we can hope to distinguish upon
the surface of the moon only very
large objects, such as mountains or
huge craters.
According to Aragos reasoning, if
we could secure a magnification Of
1000 times it would be as if we were
looking at some object on earth re
moved to a distance of 119 miles.
But this reasoning is all wrong
when applied to a star high above the
horizon, near the zenith of the heav-
ems. In this case our eyesight has
to pass through layers of air equal
only to that between us and an OBJ
ject five miles away on earth. The
problem must therefore be attacked
from another, more scientific side,
before the question can be properly
answered.
On account OF he limitations OF
vision of the human eye, even when
aided by the most powerful telescope
the figures given before mus be cor
rected. If we get az enlargement Of
ninety times the amateur can see
objects $500 feet in diameter. If
our eye could use a telescope mag
nifying 1000 times the object seen
on the moon might be only 16C feet
in diameter and 1900 lines only twen-
ty-one feet in diameter. Iut this is
only Theoretical.
Practically the case is quite differ
ent, for the power of the eye is now
the main consideration. The eye may
be trained even for astronomical OBJ
seryation, So that it sees more than
the unframed eye. But then we are
face to face with another difficulty,
that of the atmosphere. The wider
the opening of the telescope the
greater are our difficulties with the
atmosphere. The image becomes so
trembling and indistinct when looked
at through the larger telescopes that
we see hardly anything.
Theoretically We should Usave TO
secure an enlargement of g., J times
to see an object fiftyfour feet in
diameter and if we wanted the en-
larging a yard in diameter the en-
largement would have to be $4,000
times. Even if We ever get teles-
cope of this power the human eye
would not be able to see through it,
even though we place the telescope
upon the highest mountain so as TO
escape the thickest layers of the at
mosphere.
The greatest astronomers, like Sir
William Herschel, have made their
most valuable discoveries by com
paratively low-power telescopes. The
eye of man, unless some new laws Of
optics are discovered, will never be
able to see any small object on the
moon, no matter how powerful our
telescopes are made. We may see
mountains and craters-that is about
all.