The times. [volume] (Richmond, Va.) 1890-1903, 1898-02-13
THE SKIES IN FEBRUARY
THE PRACTICAL UTILITY OF As
TRONOMY SET FORTH.
Immense Distances of the Fixed stars and
How Dete' mined-PIeiades, Hyades.
Orion and Procyon Now Seen.


and chemistry. They commit a mistake,
for not even such practical sciences as
the last two named have had such di-
rect bearing upon practical and every
day life as astronomy. Without a know
ledge of that great science we should
have no accurate means of measuring
time. navigators would hopelessly lose
themselves on the painless waves OF the
sea, accurate geodetics and topographic
measurements would present insuperable
difficulties such practical and indespensi-
bic things as calendars and almanacs
would not exist. in short. there would
prevail inextricablc confusion In regards
to many things. Even such as have but
little conception of scientific matters
will readily understand that the lOca-
tion OF places by longitude and latitude
Is OF the greatest importance. The mari
ner that wants to sail for a certain island,
or a certain harbOr does not sail about
the sea at random until he inadvert-
emily alights upon his place OF destina-
ton. He knows the longitude and lati-
tude Of the latter and he sails towards
IL as directly as other circumstances will
permit. Now. mere present themselves
two distinct astronomical problems; FIRST
the obtaining of the longitude and lati-
tude Of places on the surface Of the
earth. and after these are established,
how the navigator gets there without
losing his way on the ocean. The maui
teal science is nothing but a branch Of
astronomy. and without at least prac-
tical knowledge OF it. the mariner would
be no more than the professional sol
der without arms.
THE PRACTICAL RESULTS.
The practical results OF the astromical
science enable the nautical man 20 ma
out at any time on the ocean exactly
where he is and 10 arrive where ne
wants to go. In q mere newspaper artl-
clio we cannot be supposed to enter NIL
nutely into an explanation OF the more
and less ingenious methods OF hndlng
the longitude and latitude OF places on
the surface OF the earth. and we conhne
ourselves to an example I'M each case.
Let us take a circumpolar star. that IS
one that does not set. This star viii,
within twenty-four hours, twice pass
the meridian. or, 10 use technical eN-
preston. eliminate. Let this star be OBJ
served at its upper and lower oulmina-
ton with a suitable instrument enabling
US 10 read Of the attitude Of the star
az its two EXAMINATIONS The mean or
these attitudes vii give us the latitude
OF the place. There are other methOds
which time and space forbid us TO men
ton. This for the determination or lat
titude. The longitude Of place is the
the difference of the local time, OF that
MACE from some other. Greenich, for
instance Now. the determination OF local
time is accomplished by observing
celestial object, and pertains therefore.
TO astronomy. 4 person not conVersant
with the wonderful power of mathemat-
Jcal analysis and its applicability 70
celestial bodies that are hundreds OF thou-
sands. nay. billions of miles distant from
the earth. cannot but wonder with
feeling Of awe how the distance OF the
moon the greater distances of the sun and
NANTES can be measured. and still TINS
problem is not so difficult of solution as
many others. The angle under when the
radius of the earth would appear Nhen
viewed from the moon, or the sun or a
planet. is called the parailax or the
celestial body. and when the latter IS on
the horizon il is called horizontal paral-
lax The radius of the earth being known
and also the parallax of the celestial
bodv. the distance from the earth IS
easily calculated. Thus has been found
the distance Of the moon and sun from
the earth.
THE THIRD LAW.
The third OF the three famous laws or
Kenler. which establishes the relations
that exist between the sldereal perlou9
of two planets and their resuecllNo us
tances from the sun enables MS TO ma
the distance OF any planet. its sidereal
neriod that Of the earth, and the as
tance Of the latter being known. Inc
svnodical period Of a planet. when Is the
time occupied by it I'm passing from
conjunction to conjunction, being Cd
served. the sidereal period can easily DE
conputed. This method OF finding the
distances Of the planets requires tnere-
fore. an accurate determination OF the
earth's distance from the sun, ana lot
this reason the most strenuous eAeI
have been made 20 obtain as accurate Il
value OF this distance as posslple' AS
we have mentioned before. the distance
can easily be found after establishing the
suns horizontal parallaX, ana Tor TINS
reoson il is Of the greatest Importance
10 establish this parallax. At the be-
ginning Of the last century no result nau
vet been attained that might be called
approximately correct, and II was not
until a comparatively recent time that
a Trustworthy value OF this horizontal
parallax of the sun was obtained. WIN
this a more accurate distance of the sun
from the earth has been established.
The methods employed IN a satisfactory
solution OF this important problem dis
plays an amount OF ingenuity that can
not fail 20 excite the admiration Of those
who are capable OF approaching such
mental labors. As TO the distance or
the bodies that constitute one solar
system science has placed matters on
pretty sure basis. but the ever active
and aspiring human mind was not sat
ished with this, and il has striven and
is still striving TO gage the very depths
OF the stellar universe. II does not re-
quire any special acuteness OF the intel
Iect to see that such "A parallax as that
OF the sun and the moon. or the planets.
IS no. possible in case OF the stars.
In comparison 10 their stupendous dis
lance from US the radius OF the earth
dwindlses into a mathematical point
that is. into nothing and it became in
dispensible 10 find a parallax that related
10 something incomparably larger than
that radius. 1t suggested itself to as
tronomers TO choose the radius OF the
earth's orbit for the line 10 base the
parallax OF the stars on. and this para
lax has been appropriately called the
annual parallax. The number OF stars
whose annual parallax has been obtained
with more or less reliable exactness Is
limited. the task requiring extraordinary
keenness OF observation. Thus, we have
found that our nearest neighbor in the
sidereal realms OF the universe Is Alpha
Centauri whose distance is three and a
half light years. A light year is the
space which the swiftest OF all travellers.
the light, would travel in a year. Such
distances expressed by miles. nay. even
by the distance OF the sun from the
earth would present numbers that con
M nj In mi ~