Butler citizen. [volume] (Butler, Pa.) 1877-1922, 1897-06-03
TIL + CITIZEN
The stellar Vault in June.

Liver since the time of Hipparchus,
who is called the father of astronomy,
the study Of the heavens has been car
ried ON in the most systematic manner
For many centuries the stars We're sup
posed to be immovably fixed in the ce-
lestial vault, and to be without proper
motion. 1t is true the ancient astrono-
mers supposed all the stars made dur
nal revolution about the earth as the
centre of the universe, but their idea
was that the celestial sphere, so called,
was a material crystal substance, and
that the stars We're imbedded in that
sphere and carried by it around the
earth every twenty-four hours.
The refined methods of modern astron-
omy have disclosed the fact that the
stars are not fixed" but on the contra
~ have q proper motion at various an
giles to the line of sight, and consequent
ly the positions of the stars and con
figurations of the consultations are un-
dergoing slow change. The change
is so exceedingly slow that it would re
duire thousands Of years to become at
all noticeable If Hipparchus himself
were to return to earth he would see
not the slightest apparent change III the
constellation. Incredible as it may
seem astronomers can even detect the
motion of star when that motion Is III
the line of sight They can determine
by means of the spectroscope whether
star is approaching or receding from
the earth, but the rate of the motion Is
indeterminate. 1t has thus been ascer-
tanned that Sirius, Betelgeuse, Rigel,
Castor and Regulus are receding from
us while Arcturus, Vega, Deneb Cygni
and Pollux are approaching. 1t would
be impossible to explain lucidly just
how they arrive at this knowledge, but
it is deduced from certain principles de
pendant upon the undulatory theory of
light.
Ptolemy who lived about 300 years af-
ter Hipparchus was probably the first
astronomer TO compile a catalogue of
the stars, but it is supposed by some
that his catalogue was really the work
of Hipparchus. Ptolemy was for sew
eral centuries the pre- eminent author
ity on astronomy, and his work the
"Almagest" contained the sum and sub
stance of all that was known on the sub
ject up to the time of Kepler.
1t does not require very close observa
ton to acertain the fact that different
consultations are visible at different
seasons and it is a curious fact that the
arrangements are such that the bright
est consultations are mostly visible dur
ing the long evenings, while the less
brilliant ones are so grouped as to ap
pear for the most part at the season of
short nights Thus in the long wintry
evenings the sky is adorned with such
SPLENDID consultations as Orion, Tau
rus, Leo and CAMS Major, while in mid
summer, consultations of inferior splen-
dor predominate Just at this time the
most striking groups visible in the eve
ming are Leo with its sickle, Scorpio
with its scythe. Bootes the Herdsman,
Cygnus the Swan, Lyra the Harp,
Aquila the Eagle and Corona Borealis
the Northern Crown. In addition TO
these are the beautiful circumpolar con
stellations which are visible at all sea
sons.
To- hn OH find NanIrG u
its greatest brilliancy on June A. About
ee-tenths of its disk is illuminated
and its telescope appearance is similar
to the moon at four days old.
Satrun and Uranus being in conjunc
ton on June IS viii come to the merid-
simultaneously on that evening, the ex-
act time of meridian transit being 1903
standard time at Butler Saturn is at
that instant two degrees above Uranus
and the latter may bereadily identified.
On June 81, the sun comes 10 the
northern limit of his declination and
the Astronomical summer begins. He
is on that date directly in the zenith at
noon at points on the tropic of Cancer.
The above day is also the longest of the
year, north of the equator, its exact
length depending on the latitude of the
given place. 1t is found to vary from
12 hours at the equator to "a hours at
the arctic circle. Computations have
been made to determine its length for
several different points on the earth,
and the results are subjoined:-