The Guthrie daily leader. [volume] (Guthrie, Okla.) 1893-1996, 1912-07-09
5S0l0N ~ /1&sZ a&fW OtlAEx EXxKxI 70

Juniter. the giant OF our planetary
system, is now the bright particular
feature OF the evening skies through
tts month OF July It is we'll situated
for observation. 1t iess. near the
meridian at the hour of the map, and
in0thegAbsence OF the moon. Is by far
the most luminous object IN the
bsayens GIt is more than six times
ssNbright as Vega and Arcturus, the
most brilliant of the hxed stars now
above the horizon and outshines its
reiEhbor Antares the red first mag
nitude star in Seorpio, fifteen to one.
Jupiter Ia in some respects the
most interesting OF all the planets
Its colossal bulk would contain more
than 1900 OF our earths and exceeds
that of all the other planets put to-
gether or its family OF moons sew
eral are visible only with the most
powerful telescopes. Four, however
are quite within the range OF held
glass or q good opera glass. and thus
seen, their rapid changes OF position
may be followed from night TO night
"a fascinating spectacle
The First Telescope Find
AS matter OF fact these four
satellites are bright enough to be
seen with the naked eye were they
not Host in the dazzling rays of their
great primary. All are brighter than
Nave. star OF the sixth magnitude which
hack at at the limit OF good ordinary vision
fa.l az nder Favorable seeing conditions.
-. irdeed, some persons believe they
~Atp have separated them with the unaid-
iosget tnat = Probably Imagination comes
on al occasions of vision in such cases
s,,,--.>xs;-ua came existence of Jupiters
moons was not known until Calico
glmpsed them through his nrst crude
telescope, little more than three
centuries ago They bear the his
toric distinction of having been the
very first of telescope discoveries,
on which modern knowledge of the
universe Ia based. II was not until
1892 that fifth satellite was discov
cred
The difficulty of perceiyng the four
moons lies in the fact that false rays
ealarge the planets image on the
lefiua and the images of the four
satellites are covered up by this lr-
radiation A good opera glass robs
me planets image OF its false rays
and the Jovian system comes into
view as plainly us Calico saw IL
the nlanet as a minute disc, the
moons as little, steadily shining
lolnts that weave constantly TO and
fro as they accomplish their oIbitai
revolutions
larger Tran Our Own Moon h.
Now these luminous Dlts are Iedil'
Considerable bodies. as satellites go
All but one are larger than our own
moon Satellite l.. tthat nearest the
sqlanet) Isl 2sinaf miles IN diameter
FfIe diameter Of our own moon is =
stFe2 mites Satellite H., The smallest
dof-fhe fenrlr measuresee 2,lO0 miles.
Satellite ILL., the largest is 3.3o3
faileg in diameter. larger than the
plaI1ef Mercury Thd osstermost, ~ !
is 1850 miles through
The inner satellites move with
great speed around the planet, l.,
making a complete revolution In one |
day is hours and % minutes al
distance OF 262 900 miles Because |
&fAsfxs sf2pid motion II changes night
1gwtrufn side to side OF les primary |
The revolution period OF Satellite
H. is days, IL hours and IL min
utes. of HI !, and ", about and 10
DAYS respectively The distances
rom Jupiter OF H.. H.. and W,
are $4,000 miles, 664, 900 miles and 1
lI7DO00 miles.
Following Their Motions
BY comparing distances and mo
fions il is possible to identify each /
satellite and follow its changes OF
position For instance the COM
psratively siow-moving Satellite ".
which on the last night Of June ap
pears TO the eastward OF the planet
has passed TO the west by the night
Of July /. On the night of July 4, 1t 7;
aitajns it's greatest western elonga-
ton Then il swings back towards
Jupiter aid by the night Of the 9Th
has passed behind the planet to It's |
eastward side. In the next eight p
days IL moves TO its greatest eastern
slongation and back again to theI