Omaha daily bee., 1903-03-08
IN THE ANDES.

spondence of The Bee. MIR. Per-
- cival Lowell, founder and di-
A rector OF the Lowell observatory
at Flagstaff, Ariz., and professor
OF astronomy at the Massachusetts, Insti-
tute Of Technology, to the upbuilding OF
which the we'll known Lowell family OF
this city, of which he is a member, has
SO long and so faithfully contributed. has
recently left Boston for Flagstaff to make
final arrangements for a unique series OF
explorations which he is soon to undertake
with the idea of selecting the best pos
sible sites, the world over, for future
astronomical observation.
1t has always been a serious embarrass-
ment that an astronomer in one locality
often makes observations that are appar-
emily not In harmony with parallel records
made at some other observatory. At pres
ent II is hard to tell how far. this sort
OF disagreement is due to atmospheric con-
ditions. In other words, there is no COM
mon standard of good SEEING as astron-
omers call 1t. But Mr.. Lowell, with other
astronomers, holds that there are certain
definite optical phenomena from which,
after proper comparison and study, such a
standard may be evolved-a standard by
means of which all observations everywhere
can be reduced to a common basis. Mr..
Lowelis expedition, therefore,, will be
practically an exploration, conducted in
both hemispheres, into atmospheric condi-
tions-that is, of the air itself, as the
medium through which every astronomer
must look. however high up in the noun
tains he may climb for a site for his OBJ
servatory, or however perfect his instru-
ments may be.
Moreover, Mr.. Lowell's problem involves
mara than fuat plaaFnaea ~ atnnnonharo
though this, too. is important. No one, of
course, would dream of planting a valuable
telescope In the heart OF London or Chi
cago. The clearer the air the nearer and
sharper seem all distant objects, and stars
are no exception to the general rule. Put
In a nutshell, the gist of the matter lies
In the fact that the air-whether clear or
not clear-is in constant vibration, the de-
gree Of the vibration varying according to
locality. These air vibrations, or air
waves, inevitably affect the appearance of
The stars and other heavenly bodies as seen
through a telescope or recorded by a
camera. In every tract or space of air,
moreover, several separate systems Of vi
brations. in each of which the waves are
Of a regular length. though this length
may vary from a fraction of an inch in
one system up to several feet In a second
VI - NhhANf "a oAhago " bO HUT
playing with one another.
Although we are not ordinarily con-
scious of them, these restless waves Of air
affect eur seeing in much the same way
as when we open our eyes under water and
look up toward the sunlight. The differ
ence is that We are used to being under
an ocean Of air and we are not used TO
being under an ocean OF water. Under the
water We see the sun as a blur, but 50,
too, we actually Sc It through the air. We
look out into space through a vibrating
medium, and this will be our fate to the
end OF time. We shall never see the sun,
the planets and the fixed stars with alb
solute precision.
Fortunately for the astronomers, there
are times and places OF relatively good
seeing" In these places the general ac-
tion of the air waves can be accurately
figured out so as to bear a definite rela-
tion to the diameter of the object glass Of
ones telescope. This sounds a little hard,
but the principle is really very simple, II
an air wave from crest to crest, that is,
is shorter than the diameter OF the glass.
then an inequality OF refraction results,
which c~onfuses the thing that you are
looking at. II, on the other hand. the wave
Is longer than the diameter OF the glass,
then the image merely seems to sway back
and forth as a whole. Ideally good seeing
is neither of these. II is where the wave
lengths are practically the same as the
out whether the air waves are longer or