Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1907-04-11
THE APRIL SKIES.
The Planets, stars ana ConsteIIations-
The Rings of saturn.

| In tho month of April the evening sky
changes It's character; for the brilliant
groups Of stars which grace the heavens
in winter are yielding their places to the
less prominent groups Of summer. In the
West Orion. in the Southwest CAMS Major.
! in the Northwest Auriga and Perseus sink
| lower and lower as the evenings follow
each other. while CAMS Minor. Taurus and
Geminl succeed them and close tho list
OF the brighter star groups. In these
groups are found no less than eight of the
| ffteen stars visible In Northern attitudes
winch are still called of the first magni-
tude'-a phrase which cam. down 10 us
from the Greeks at the beginning of the
christian era. when size and br ghtness
We're considered to vary in like prnport on
turning TO the South and East. Cancer
Leo ana Virgo follow Gemini in the zod-
acal belt, and corNus is conspicuous in the
southeast The bright star Arcturus IN
thc East. which may he identified by fol-
lowlng the curve suggested by the handle
or tho Dpper is in the large group Hootes
near which may he found the smaller
groups Corona Boreals and Coma Bcreni-
cos. In the North Cassiopeia t'rsa Minor.
| rsa Major and Draco circle about the
pole in the region which never goes below
our horizon.
The leading planets of our solar system
may all I've seen this month. Mercury near
the middle Of the month ONLY. tho others
on any clear night. Jupiter ard Ncptunc
are visible N the evening and set near mid
night. while Mercury, Venus. Mars. saturn
and Uranus rise after midnight and shine
until the dawn overpowers them
Jupiter Is brilliant IN the constellation
Gemlni. outshining any OF the stars in the
western sky. Those who are Watching the
movements of its satellites will find the
ilst OF interesting positions A fun 90 thus
month Transits of satellite l. and its
shadow occur on the 9Th 18th and I'D: ~
satellite II. and It's shadow on the Sth
and 10Th. Fcnpses of all four of the
bright satellites may also be- noted. Satol-
lite |. always enters the planets shadow
when hidden behind the planet. but il
emergence from the shadow may no oh
served on the eth at about 90 D. m. the
18th at 1l.o5 p. m, the sd al 30 p m. the
Goth az 9.25 D. m. Similarly. satellite n.
emerges from the planets shadow on the
18th at about 725 D. m. and the 2lth at
10 p. m. Satellite III. may DE seen to enter
the shadow on the 2sth At about As u. m.
and will be invisible for three hours and
ten minutes. Satellite ~. Is eclinscd on
the LIST entering the shadow at about $40
p m. and emerging two hours and fifty
minutes later
Neptune is not far from jupiter Il |
requires telescope assistance to he seen |
and on the LIST is In right ascension LII |
4Sin and declination y % deg 10 min
The morning group Of planets IS led by |
Mars. which rises on the LIST at one o'clock |
and on the Both al II IS p. m. This planet |
is now increasing apprcc,ably in br ghtness |
as 1t nears the earth. on the LIST 1t is 49,
"""o miles, ana on the 31th. 60 100000 !
miles distant. In the telescope the white |
cap about the southern pole is now visible |
and also the leading dark and bright
areas, giving an earnest OF the markings |
which will be seen more distinctly in tho
summer months
Uranus follows Mars. rising ON the let at
! 30 q. m, and on the 35th at 1876 p. m.
1t may be found by pointing the tcles-
cope AT right ascension 1Sh. 55m. and de-
clination south % degrees and 70 minutes
II is 90 degrees from the sun ON the Sd.
and begins to retrograde among the stars
on the nth
Venus rises On the LIST az SIS r. m. and
one minute earlier each succeeding morn
ing. The sun. however riscs forty-hv
minutes earlier at the close of the month
than at its beginning. so that Venus Will
not appear as long before sunrise a the
mornings follow each other. But It VIII
be many weeks before IL ceases to herald
tho dawn as now with It's brilliant light.
Mercury may be seen, bur with diffcuNy
for few mornings near the nth. on that
date 1t rises fifty minutes before the sun,
and IS OF about one-half It's greatest
brightness.
Saturn Is the last to rise but 1t Is not
the least interesting of the planets In
fact IT begins this month series Of
events, which lasts until next January
and which will attract much attention
among all observers who have telescopes
These events occur in connection with the
of the rings, which greatly
ouzzied Calico, who first noted IT. Huy.
yhcns explained the phenomenon a half
century later. The rings of Saturn lie IN
| thin plane. which maintains a constant
lngle with the planets orbit about the
sun. Twice in etery revolution of the
planet about the sun. the sun comes into
he plene NJ the ring. Just as twice each
'ear il seems to cross the plane of the
'arths equator. In the case Of Saturn, ,
which takes nearly. thirty years TO revolve
ibout tho sun, these occurrences are
learly fifteen years apart. The earth as
{ moves about the sun is brought into
'arious relations with the planet in the .
months which precede and follow the suns
rossing the plane of the rings. 50 that s
ieWed from the earth the rings may DIS
ppear twice. The rings shine by reflected r
light from the sun. II may happen that s
he earth and sun may be on opposite !
ides for a few days: whore this occurs \
he dark side of the ring is turned toward {
he earth, and makes a black bar crossing
he disc of the planet
unity for Witnessing all the possible phe- ]
lomena. Saturn rises on the lat of April
t AIS a. M, and four minutes earlier each Is
ucceeding morning. On the 18th the earth
ONES into line with the rings and they =
viii probably become invisible. AS the
lane Is too narrow to show the line OF I
ght which really exists, From April IL :
o July % we face the unillumned side of
10 rings, as the sun Is north and the earth |
outh OF the rings. In this interval the !!
ings Will appear as a narrow black bar n
rosslng the planet, 1t is possible that t
hin limo Of light may be seen marking a
he place Of the rings on either side of the !,
all In 1AS under similar condition tho d
,rge Cambridge telescope succeeded in 6
lima hat