Evening star., 1897-07-28
TOMORROW'S ECLIPSE.
The Shadow Of the Noon Will Be Cast Upon
the Earth.
An Interesting Celestial Occarrence
simple iCo.triv.nce.

throughout the United States 1t will be-
gin here, calculated in eastern standard
time, at $50 am, and will end at 1I:15
am. the middle of the eclipse, when the
obscuratian will be greatest, occurring at
1880 am. At this moment about five
twelfths of the suns diameter will be COW
cred by the moon. 1t is the last solar
eclipse visible in this country before May
81, 190O and while it will be destitute of
any novel features from scientific point
of view, nothing less than a .otal eclipse
being worthy of the stu.lious attention OF
an astronomer, it will inspire much pop
ular interest. In Mexico and the northern
part of the West Indies it will present a
spectacle of unusual slngulari:y and
beauty. To comfortably observe the eclipse
in this latitude all that is needed are two
and five inches wide. so that both eyes
may be used, with the blacxcned surfaces
together and bound together with elastic
bands.
The Path of the Eclipse
On Thursday morning the shadow of
the moon caretring thr orgh the empty void
Of external space encounters the earth at
3 O'Clock and falls in IN oval spot upon the
Pacific ocean off the western coast of Mex
leo Spreading from this point it extends
forth far as the fifty-sixth parallel OF
north latitude and south to the twentieth
parallel of south latitude. Cutting this
broad swath. so to say. of about five thou
sand miles in width. it sweeps in an east
erly direction across North and South
America. and then taking a southeasterly
course leaves the earth about pm at d
point in the southern Atlantic ocean over
5000 miles from the starting point. During
these six hours 1t has partially obscured
about oEe-fifth Of the surface of the earth
The axis or central portion of the shadow
known as the path of annulus, travels from
Tecapan. in Mexico, across the gulf, skirt
ing the northern coasts of the West Indies
and finally leaving the continent at Cape
st. Rogue. All places on this belt behold
the sun at the middle Of the eclipse as an
extremely slender ring of brilliant sunlight
forming golden frame for the dark globe
or the moon. At these places the eclipse is
annular. At all other places within the
shadow the phenomenon is a more or less
one-sided affair, only one side or edge OF
The suns disk being obscured.
Some Curious Facts.
1t may not be devoid of interest to con-
slider briefly the circumstances which give
rise to an annular rather than TO a total
eclipse. 1t Is curious fact that although
the suns diameter is four hundred times
as large as that of the moon, their disks as
viewed from the earth appear to be of the
same size. This is effected oy the singular
but by no means necessary coincidence that
the distance of the sun bears the same
ratio to the distance of the moon as the
diameter of the sun does 20 the diameter of
the moon. This ratio is approximately 400.
Although the disks appear to be the
same. the ever varying distance of the
moon from the earth, now nearer, now fur
ther away, effects a corresponding change
in its apparent diameter, so that it is some
times larger, at other times smaller than
the sun.
II the moon is near to the earth it's disk
is large enough TO cover the sun. and
total eclipse results at those places along
the track of the umbral or inner shadow.
If. on the other hand. as is the case in the
present eclipse. the moon happens to be
further away from the earth than it's aver
age distance. its face appears smaller than
that of the Sun. The result is that the
moon is not large enough to cover the sun.
and a partial eclipse takes place, one-sided
in regions off the central line of shadow
and r'ing-shaped or annular in places on the
central line.
4 Splendid Spectacle In Cuba.
For example, the axis of the shadow
passes about twenty miles north of Ha-
vana. An observer Of the eclipse at this
place at 9:45 sees the moon centrally pro-
jected upon the sun, but not quite hiding
1t from view, leaving bright ring Of light
about -hundredth of its diameter in
width. At Havana itself the moon will
be projected little further up in the sky,
and the only part of the sun. visible at
9:45 will be thin, delicate crescent of
light somewhat longer than scmicircle.
This will slowly increase in breadth until
finally, toward noon, the sun will really,
and let us hope prophetically, shine again
In undimnished splendor on the now DESC
lated country Of Cuba.
During this eclipse the moon. a globe
2.16S miles in diameter. is 10000 miles
from the earth. while the sun. one vast
luminary, SCI. 400 miles in diameter, is o.
100000 miles away. The apex of the dense
shadow within which the sun would be
totally obscured. falls short of the earth
by about 200 miles. The average veIoc-
ity of the shadow of the moon as it drifts
across the earth, like the shadow of a
summer cloud. Is about twenty-four times
that of a fast express train.
The next total eclipse Of the sun will
take place January y, 1885, the path OF
totality extending across Central Africa
and India. Although the duration Of total
ity Is only two minutes, extensive prepara-
tions are being made for its proper obser-
walton. 1t will be invisible here. The next
eclipse of the sun visible in the United
States will occur May u, 1860, and will
be total. the line of totality reaching from
Louisiana to Virginia; duration of totality,
two minutes. 1t will. therefore, be seen
that astronomers have only four minutes
during the rest Of this century in which
the sun may be studied by direct observa-
ton.