Delaware gazette and state journal. (Wilmington, Del.) 1883-1902, 1900-07-05
THE SKIES in July.


| siipO' Wtit PfUsUub hbT puuSGS uH IOllOWS
First quarter, on the 4th; full, on the
| 18th; last quarter on the 10th new, on
the Goth. She will be 10 apogee on the
3d and 3lst, and in perigee on the 18th.
The sun, which on the lst OF the month
was only 10 minutes of arc below Its
maximum destination - that is, the
summer solstioe-will traverse in the
course OF the eEtire month an arc OF 8
degrees minutes. At the beginning
Of the month ard at the latitude OF
baltimoIe the sun will rise and set 30
degrees 80 minutes north of the true
east and west points of the horizon,
and on the last day of the month very
nearly "a degrees. The expression OF
tho SUMS rising in the east and setting
10 the west is strictly true only on two
days OF the year, the beginning of
spring and autumn, since then the sun
Is on the equator and its diurnal path
o great circle, whilst ON any other day
its path Is small circle. On the LIST
OF the month and at the latitude Of
Baltimore the sun will end shining
through windows that directly face the
north at 20 minutes past 7 a. M, and
on the last day about 8 minutes past
Ga. m.
| The planet Mercury, which on the
ID OF the month will reach its greatest
eastern elongation, will be in the con-
stellation Cancer throughout the entire
month, Venus will be in Gemini and
cease. to be an evening star, but about
the middle Of the month begin to act
as morning star, though, since 1t rises
when the morning twilight is far ad-
vanced, 1t will not be in favorable
situation for observation. On the 9th
l al IN L. T. T.
conjunction with the sun; that Is, In a
straight line between tue sun and the
earth, and consequently invisible. The
interval between two conjunotiops Of
the same kind of planet is called its
synodic period, which In the case Of
Venus Is 584 days, while her sidereal
period-the time of complete revoiu-
tion about the SUMS only 225 days
Consequently Venus will remain a
morning star foi 202 days and then be-
come an evening star for as many days.
Since Venus becomes morning star
on the 9Th of July, il will continue to
not In that capacity until April 26th of
the coming year. Mars is in Taurus
and acts as a morning star. 1t will Use
abont O'Clock in the morning. Or all
the. larger planets Mars has the longest
synodio period, viz, 7S0 days. or the
numerous peculiarities OF Mars the
fact of the period OF the inner satellite
Phobos being the shortest in the whole
solar system is one. Fhobos reyolyes
about its primary 10 the remarkably
short time of hours and 80 minutes,
which is not one third of the day OF
Mars. 1t Is owing to this fact that II
rises in the west every night for the
Inhabitants of Mars, il there are any,
and sets In the east after about five
and half hours. Jupiter 10 In Scorpio,
grsatly enhancing by its ulster the in
ttinsic beauty OF that constellation. At
about o'clock in the July evenings il
is on the meridian, setting about 9
O'Clock in the beginning of the month
and few minutes past midnight at the
end. Not fur from Jupiter, toward the
east, the fine planet Saturn shines In
the neighboring constellation OF Sagit.
tarious. 1t gets about two hours later
than Jupiter, thus being visible nearly
throughout the night
Tbs division of the earth's surface
into the different zones is not an arbi.
trary arrangement, like the division Of
the land into continents, empires or
states. There is an astronomical reason
for tho division into zones. The bound
airy lines OF the torrid zone-the tropics
OF Cancer and Capricorn-a also the
boundary lines of the SUMS apparent
annual motion north and south, and the
lines that separate the temperate zones
from the frigid-the polar ciroles--pass
through the POLES Of the ecliptic. When
the sun is at the summer solstice the
day is longest in all places north Of the
equator, but the length Of the longest
day depends upon the latitude Of the
place, On the Arctic and Antarctic IL
is exactly "a hours; In fact, on that
day the sun does not set and We see the
midnight sun due north. While at the
Arctic circle the maximum length of
the day Is "a hours, ii is whole month
only 81 minutes north of it and at the
pole six months. IL Is somewhat per-
picking to not few that while the
sun has to sweep through large arc
OF about II degrees from the equator to
increase the longest day by one hour it
only sweeps through an arc of less than
degree from the polar circles to 10 .
crease the longest day by whole
month. The matter, however, becomes
clear by considering that the ecliptic--
the apparent path of the sun-outs the
parallels of latitude at smaller angles
with increasing latitude, so that the
more and more to parallelism with the
equator, and that as matter of course
its motion in declination becomes tie
slower the nearer It is to its northern Or
southern boundaries, the solstioes.
There is nothing more interesting than
the two-fold motion of the sun in right
ascension and declinatiop, upon the
former OF which its motion among the
/ consultations of the zodiac and unon
the latter OF which the SEASONS and the
extent and limits of the terrestrial
zones defSnd.
A very interesting question is how
far one would have to rise above the
surface of the earth in other zones than
the frigid in order to see the midnight
sun. As, of course, we cannot be ex-
pected to enter into calculations in
newspaper article that must needs be
within the power of comprehension and
the knowledge OF the general reader,
we simply furnish results The eleva-
tion in the latitude of Baltimore
whence to see the sun at midnight at
the time of the summer solstice would
be 405 miles, while at the time of the
yernal equinox tspring) IL would be
2,3il miles. At q latitude of Z degrees
81 minutes at the time Of the summer
solstice the elevation required would
be equal to the earth's diameter, and at
at latitude 30 degrees at the beginning
of spring 1t would have the same ele-
walton OF the earth's diameter At the
tropics the elevation at the beginning
OF summer would be about the earth's
radius.
OF all the consultations that are on
1 q, Il s.. n - Al =