Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1874-12-30
AstrOnOmy.-Article Cd.
WatertoWn Wis, Dec. 21st. 1877

in your issue of Dec. I'd, to four remark bic
double stars which at 6 o'clock P. NJ Of
that date, appeared in the form of a Greek.
cross in the south east. At o'clock P. NJ.
that evening the cross had swung round 10
the south, changing its position just 80 de-
grees, o" $50 for every hour, the two stars,
AIge''ib and -4lphro'z forming the east side
Of the square resting on the meridian or
north and south line.
1t is so days since the date of the last
article; in these 80 days the earth has
moved 80 degrees in its orbit round the
sun. The equinoctial line and all other
circles are divided into $500; there are
3654 days in one year, SO tue earth moves
few seconds of space less then 10 every
day, but this movement is distinct from
the rotary motion of the earth on its own
axis from west to east, the velocity of this
diurnal motion is at the rate of $4,000
miles per day.
Knowing the diameter and circumference
of the earth, scientific men have computed
the weight Of our earth to be {, 700, 900, OOO,-
900, 900, 100000 tons, that is to say; six
thousand million million times a million,
yet this stupendous body is rushing through
the abyss of space with velocity of l 900
miles per minute or about Is miles during
every pulsation of the heart. But the
| in aric with no ho6 Il
which it is revolving, is as a single grain of
wheat compared with the bulk of four
! bushels.
A very simple way to mark the particular
motion of stars independent of the daily
motion of the earth, is TO observe along the
wall of a house ,he position ofsome particu-
lar star in the heavens. Note well It's dis
lance flom he wall it apparently moves
from east 10 west, note also the moment on
your watch return the next evening at
the same moment and note the space it has
passed over, it will be one degree in the
earth's orSit. This is IN fact Tie way in
which observations are taken in great OBJ
servatol les. This great equatorial telescope;
which will sometimes cost 20 thousand
dollars, as did the one in Chicago; are set
and the cross hairs brought to bear upon
star. The exact moment is taken on
clock, and the return of that star 10 the
vertical hairs in the telescope is called a
sideral day, which consists OF 90 hours,
56 minutes seconds. The astronomical
or solar day begius at noon and counts
round to poon the next day, from l to "a
hours consecutively, making no distinction
for or at the II or midnight hour. The
civil day or meantime, begins at the hour
of midnight and counts round to IL or
noon and then on 10 II or midnight, so
that it consi,s of 2 set Of hours of II each,
the forenoon and afternoon hours. There
fore the civil day is always II honrs in ad-
vance Of the Solar or astronomical day so
that the 23d hour oithe 2lst of December as
Economical tme is ii o'clock A. NJ Dec
the 22d civil time.
1t may appear strange to many people to
be told that the sun is really correct to
true meantime only on days in the year,
viz, on the 9th of April, the 18th of June,
September lst and on the Gath OF December
While again, on the 18th of February it is
l Il min utes slov. On The 18th of April
it is miuu es Jass. On the 25th of July
it is g. minutes sIoao and on the 1st of Nov.
it is l644 minutes fast. 1t is the sloa0ness
Of The sun in setting in January and Feb
ruary that causes US 10 observe the length
ening Of the day, particularly in the eve
ming " bile he is very slow in rising in the
long dark mornings. While again; it is
to his earliness in setting in the fall eve
nings, we owe the shortening Of the days
at that season.
On the evening of the 22d of December
at ?. NJ. the Equinoctial Colure and the
first point OF dries will be on the meridian
OF Watertown and on that of all places due
north and soush Of it from the north to the
south pole, that is, on the same meridian
of longitude, and the same moment of time
at all these plans.
AS the mariner starts on his voyage,
taking his bearings and reckoning from
the meridian of Green wich, east or west for
his Longitude. The mariner may fad an
island or rock and fix its locality by
marking lis latitude and longitude so that
it can be easily found again. So with the
| Astronomer, He will start from the first
point Of dries OR of the verBal equinox,
marking down his observations in hours
and minutes of time aud calling his eastern
and western measurements right ascension,
Instead OF longitude, and Defamation north
or south as the case may be, for latitude.
While for greater certainty he has the d's-
lance OF any and every star from the north
CIR south Pole, called North Polar Distance,
Abbreviated N. P. D. or South Polar Distance,
Abbreviated S. P. D. Please observe: Right
ascension represents the longitude of star,
reckoning always eastward from Aries,
round to the point of begir ming 1900.
Taxing AIgensd as starting point, the
point Aries is l5o due south and Azphratz
is ! 80 due north of Algenib, range your eye
along these two stars and you will find a
oright star Caep.i, way between Azphratz
and the north Pole star, Polaris or Ahucca-
bah. as 1t was called by the Hebrews of old.
The Pole star is of the Sd magnitude,
there is vacant space all refund it, but be.
sides the line of three stars just mentioned
it is always to be found by referring to the
two stars called the pointers, it is presumed
that every person knows where to End the
constellation of the great Bear or Ursa
Major, generally known in America as the
D:pper.
The Dipper is perhaps the best known
constellation in the heavens, it never sets
or goes below the horizon or out of sight