The Arizona sentinel., 1889-04-20

The star in the upper left-hand
corner of the oblong of Orion is Betel-
geuse. TwenJy-six degrees east of this
star is seen another bright star,
Procyon, in the constellation CAMS
Minor, the Little Dog; lower down,
twenty-six degrees from PrOcyon and
the same from Betelgeuse is Sirius, the
Dog Star, the three forming an equilat-
eral triangle twenty-six degrees on
side.
Sirius is the brightest fixed star in
the heavens. He is two and one-half
times as bright as the average first
magnitude star, and must be vastly
larger or more brilliant than our sun,
since his distance is so great that it
takes light, travelling at the rate of
1S6, 900 miles per second, more than
fifteen years to reach us.
There was a mystery about Sirius
for long time. He was observed to
move about in a strange way. For
few years he would move in one direc-
ton, then he would move in another
direction. 1t was suggested that the
motion was due to a companion star,
which did not give enough light to be
visible, but which revolved around
Sirius and pulled him in one direction
and another. 1t was even calculated
in which direction he ought to be from
Sirius. This idea was justified by the
Il in, 1890 Of Il,
tude star in about the calculated posi-
tiOn. This faint star must be of great
size to so affect Sirius, but its surface
has probably low light-giving power.
The ancients seemed to consider
Sirius responsible for the extreme heat
of summer, since they named forty days
near the middle of summer the ''dOg
days." when Sirius was not visible in
the morning or evening. On March l
Sirius sets about l a. m. He sets
earlier and earlier until he sets so soon
after the sun as not to be visible, and
can not be seen for forty days, after
which he rises a short time before the
sun in the morning. These forty days
were CdllCu Gu6 -QOS udyS.
Almost directly overhead is seen a
bright star. This is Capella. the lead
ing star in the constellation of Auriga,
the Charioteer. 1t is associated with
four other smaller stars, forming
somewhat irregular pentagon. Toward
the east, and about one-third the way
from the horizon to the zenith, is
Regulus. The welEknown sickle is
seen extending northward and upward
from Regulus at the end of the handle.
There is a remarkable variable star
which will amply repay the little
trouble required to find it. Imagine
a line drawn from the Pole Star to
Capella; turn off to the west at right
angles to this line, and at half its
length is seen a moderately brighter
star.
This is B Persei. or Algol, the cele-
brated Winking Demon; or, another
way to find it: About one-third the
way from the zenith to the northwest
point is seen bending row of stars,
the convex side toward the western
horizon. South and west of this row,
which marks the constellation Per-
seus, is Algol, associated with three
other smaller stars to form a rhom-
bold Now the peculiarity about this
star is that its light is variable. After
shining like a reliable star of the Sec
ond magnitude for two days and four
teen hours, he begins to grow fainter,
until, at the end of three and half
hours he is Uf only the fourth magni-
tude. He then grows brighter, and at
the end of another three and a half
hours is again of the second magni-
tude. The period of variation is about
two days, twenty hours, forty-nine
minutes, and so, when the time of any
minimum, as the darkening is called,
is known, following minima may easily
be calculated. Two minima are here
given: March 2, 9:45 p. M; March 5,
$50 p. m.
1t will be advisable to identify the
star from the directions given at about
$50 in the evening, and then watch
for it at the proper hour in its changed
position due to the earth's rotation.
Astronomers are not agreed as to
what causes this remarkable periodic
diminution of the stars light, but the
general opinion is that a large dark
body is revolving around the star at
frightful speed, and partially eclipses
the star at every revolution. TIL
period seems to be shortening grad
ually, and if this is so the satellite is
approaching the primary, and will
ultimately strike it. The force of such
a collision would be sufficient to make
united bodies shine out with wonderful
brilliancy. There are many variable
stars in the Heavens, but their varia-
tions are not so great or so frequent as
those of Algol. The Arabiaus seemed
to be aware of this winking property
of the star, since they gave it the name
Algol, or the DemOn.-Pittsburgh Dis
patch.
Defective Acoustics.
'What an odd echo this room hasm