Evening star. [volume] (Washington, D.C.) 1854-1972, 1895-03-09
SHUT OFF FROM THE SUN
A Total Eclipse of the Moon Will Occur To-
morrow Night.
An Interesting Description of the
Phenomenon md the Causes Which
Bring 1t About.

Iilsnl Ihe observation VIII be total at
Washington and will be observable through
out North and South America, western
Asia, Africa and will involve vast range
of the Pacific ocean. Lunar eclipses are
more general than solar eclipses, and &C.
cur when the earth, coming between the
moon and the sun, intercepts the light and
throws a shadow on the moon. This can
happen only at the time of full moon, for
1t is then only that the moon is in opposi-
tion The moon must also, at the time Of
observation, be in the same plane as the
shadow of the earth, which means the
plane of the ecliptc in which the latter
moves. As the orbit of the moon describes
an angle greater than five degrees with the
plane of the ecliptic. it may be in OPPOSE
ton without falling within the shadow CT
the earth. If the orbit of the moon lay
exactly in the plane of the ecliptic she
would be eclipsed at every full, and
would eclipse the sun at every change"
The moon first enters the pennmbra.
which is the incomplete shadow interview
ing between the light and the true shadow.
Thence it will pass through the umhra,
region of total shadow, and thence on
through the opposing penumbra into the
region of light.
Duration of the Phenomenon.
The time of the moons contact with the
penumbra will be 7:45 o'clock. The time of
contact with the umbra will be S:5i, and
the observation will be total at 1852. The
middle of the eclipse will be attained at
0:39 and the totality will end at 11:27. The
moon will pass out of the umbra at 1928
and out Of the opposing penumbra at :21
a. m. At the time of contact the moon Will
be two hours thirty degrees east of the
meridian. An eclipse of the moon begins
On the east side of the disc and ends on the
west, while an eclipse of the sun begins on
the western side of the disc and ends On
fha CfQ 't,nn xrara hnv n
per year is four. two each for the sun and
moon, and a.; each is as long below the ho-
rizon of any particular place as above 1t,
the average number of visible eclipses is
reduced to two. Total eclipses occur in
cycles. The moon passes from one node to
another in 113 days. making the period be-
tween two successive eclipses of the sun or
of the moon. The moons nodes retrograde
in the ecliptic at the rate of nineteen and
one-half degrees each year, thus complet-
ing backward revolution of the ecliptic
In eighteen years and two hundred and
twenty-five days Thus there would be a
regular period of eclipses If any complete
number of lunatiOnS were finished without
a remainder. This, however, never hap
pens.
Regularity of Their Return.
After 223 lunations or eighteen years.
eleven days, seven hours. forty-two min
utes and thirty-o.le seconds. the sun, moon
and earth reattain nearly their relative
position that there will be a regular return
of the same eclipse for many ages This
period was the discovery of the Chaldeans,
and by them was called Saros. Therefore.
If to the mean time of any eclipse of the
sun or moon the Chaldean period be added.
you arrive at the date of the return of the
same eclipse. The periods Of the moons
contact with our shadow cannot be COM
puted with as perfect nicely can eclipses
OF the sun, where solid body cuts across
the disc.
At present lunar eclipses of very lit
tie astronomical moment, though some
times they are awaited of for the occulta-
ton of small stars. No especial prepara-
lions being made here for the ap-
preaching observation. but it will be watch
ed through an ordinary equatorial tele-
scope.
At this eclipse the moon will be very
close 20 her node, though if she We're
within twelve degrees of her node at her
full she would be safely within her
ecliptic limits. The length CT the shadow
of the earth is nearly four times as great
as the distance of the moon, and the
breadth of the umbra of the earth at the
moon varies from 5.2:::5 miles to 6,365 miles.
Tomorrow night the moon will roll through
Coca miles of this shadow.
Effects Upon the SupcrstitfOus.
Eclpses have been more patiently studied
than any other phenomena of the universe.
In the ages that have passed they were
locked on as awful deviations from the
laws of nature. Usually they We're tokens
Of divine displeasure. Among some nations.
in China, the study of eclipses was
policy of the state. so that the prediction
of them lent prestige TO the wisdom of the
rulers, and this used q club over
the heads of the masses. The aborigines
of Mexico thought that an eclipse meant
that the Great Spirit in afiiction. In
the north the aborigines thought that the
moon had been wounded in fray with
heavenly giants or was being engulfed by
sc me huge fish.
The prediction of eclpses stood our own
Columbus in good stead when wrecked at
Jamaica, as related by Almagest.
The moon has been of especial value to
astro nomy in the determination of the
form of the earth, the distance of the sun
and the magnitude of this system.
All the city will be looking Inoonward to-
morrow night.