The Washington herald., 1922-06-06
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Notes
qndConmcY
'oLARIs Is BRIGHT
AND USEFUL STAR
TUESDAY, JUNE q. Isz.-

,oLARIs Is BRIGHT
AND USEFUL STAR
One of the most remarkable stars
a. the northern hemisphere, and 10
nsvigators the most important. is
our familiar poie-star, Polaris.
Alpha in the constellation OF the
lesser Bear. or Alpha Ursae Minoris
as it is labeled automatically.
! Polaris. as nearly everyone knows.
T. the second magnitude star at the
end of the handle of the Little Dip
Fer. It is found most readily by the
aid of the Pointers OF the Rig Dip
per, which are the two stars In the
poWl Of the dipper Located farthost
from the handle. line drawn
through these two stars and eH-
tended a distance equal to about
hVe times the distance between
mem brings US to Polaris, which
Is yellowish in color and stands
apart from any other bright star.
IN the spring Of the year the
Greater Bear or. as we call IL, the
big Dipper, appears high in the
early evening sky east OF the n1er-
dian. We can then more easily find
'Polaris with the aid u the Point
ers than In the late fall and winter
evenings when the Big Dinner lies
nearly on the horizon ana is usually
hidden from view by trees or
buildings
A small telescope will separat.
Polaris into two stars. The COM
panion star is a faint. white star
OF the ninth magnitude. distant from
Polaris only eighteen seconds OF arc.
The least distance between two
stars that the Unaided eye can de-
j.. q hnH
Twenty years or SO ago IL was
discovered by means OF the spectre
scope that the brighter star was
also double star. The two com
ponents were too close together to
be separated usually in any tele-
scope. Later Investigations showed
that the brighter star was triple.
that rs. IL consists Of three suns
The faint white companion star
forms with those three a system OF
-four suns revolving about a COM
mon center OF gravity.
Still more recently IL has been
discovered that the brightest OF the
stars varies reslaurly in brir-~u---
in a period OF nearly four d.ys %
belongs to the important class Of
stars known as Cepheid variable
stars whose changes OF light. Il Is
believed. are caused by periodic in
ternal diturbances. with one er-
lception Polaris is the nearest TO the
earth OF all the Cepheld variables
which are in general at great ais
tances from US. Latest measure
ments OF the distance of Polaris
show that the light Of this star
takes two centuries to travel to the
earth at the rate Of $4,000 miles a
second. that is. its distance is about
200 light years.
Like all Cepheid variable stars,
Polaris is a giant star. It gives
forth about 525 as much light as our
own Gun. II Polsris and the sun
were placed at a distance OF thirty
three light years the sun would be
a NTH magnitude star, just within
the range OF visibility Of the naked
eye. while Polaris would outshine
Sirius, the brightest star in the
heavens.
AS a practical aid 20 naviEators
and explorers Polaris is unsurpassed
In Importance by any other star IN
the northern hemisphere. II IL now
located within one degree and four
teen minutes Of the true north pole
of the heavens which lies on the
line connecting Polaris with Miza-.
the star at the bend Of tEe handle
OF the Big Dipper. Its distance from
the pole will decrease until the year
20s5. when il will be a little less
than a degree away from It After
that its distance from the north
pole of the heavens viii gradually
increase again.
AS is well known 20 naviEators
the altitude Of Polaris above the
horizon is equal To the latitude 81
the place Of observstion-By Isabel
NJ. Lewis, OF the L. S. Naval Observ-
atory.