St. Landry clarion. (Opelousas, La.) 1890-1921, 1910-04-09
. FEW CONDENSED
FACTS ABOUT HAL
LEY'S GREAT COMET
By 4. W. Griggs in Scientific Amer

lean.
A few facts presented in condensed
form may possibly interest the read
ers of the Scientific American who
wish to follow the course of Halley's
comet in the heavens during it's pres
ent appearance.
The last perihelion passage occur
red on November 18th, 1885. The
present perihelion passage will occur
on April 10th, 1910. The perihelion
distance will be 0.578, and the aphe-
lion distance will be $3.50. The ec-
centricity is 0.967, the longitude of
ascending node is 81 deg. Is min,
the node and apsis angle is III deg.
Az min., the inclination Of the orbit
is (162 deg. IL min.) II deg. 48
min.-,the longitude Of perihelion
305 deg. and the motion is retro
grade, in other words, opposite to
that Of the planet. The diameter of
the nucleus cannot be stated with
anything like accuracy at the pres
ent time, but it is not likely to ex-
coed 10000 miles.
At the end of February Prof. Ber-
nard Of the Yerkes Observatory es-
timated the tail to be $4,000, 900
miles long. Just before and after
perihelion passage the tail will be at
least that long, and probably longer.
The comet is fast approaching it's
periheIion point, or point nearest the
sun, where, as We said, it is to ar
rive on April goth. During the
months Of February and March, the
earth and the comet are racing on
practically parallel orbits, 10000
600 miles apart on opposite sides Of
the sun.
The comet first crossed the earth's
orbit about March 10th, at a point
where the earth will arrive about the
middle Of next October, but FAR
above where the earth will be, 30 to
speak, for it will ba some 100000
miles above the plane of the ecliptic.
In April the comet will emerge from
behind the sun. and will become Wis
ible to the naked eye in the eastern
sky before sunrise.
On April 10th, when the comet
will swing round the sun, it will be
100000 miles away from the Jun.
its velocity will be 26 miles a second.
The earth travels at about 19 miles
a second. On May End the comet
will traverse the orbit Of Venus,
some 100000 miles above the plan
ct. In other words. an astronomer
on Venus would find the comet j far
more impressive spectacle than a ter
restrial astronomer. AS it rushes on,
Halley's comet pass between the
earth and sun close to It's ascending
node. On May 18th the earth will
be 100000 miles away from the
nucleus or head, as against 5000
600 miles in 1885. Moreover, OH
Nav 18th the earth will be e~nyeloped
in the comets tail for a few hours.
A few days later the comet viii Be
visible in the western sky after un-
set with a is deg or 20 deg. splen-
d r. After that it will speed away
from the solar system. The last
glimpse Of it with the naked eve viii
he obtained probably at the end If
June. II will not r4appear for sew
enty-fse years.
Halley's comet is noteworthy be-
cause It was the first comet for Il hich
an orbit was plotted and a time table
calculated. It has a history more OF
less Identified With the history Of
human thought and civilization. The
saperstitiaas dread with which it
was regarded in medieval and ancient
times sNayssf many Q monarch. e