SOUTHERN
SKY
MARTIN GEORGE describes the solar system’s changing landscape
as it appears in Earth’s southern sky.April 2014: Mars at its best
As evening twilight fades
away, the largest planet draws
attention to the northwestern
s ky. Jupiter shines at magni-
tude –2.1, noticeably brighter
than any star. It lies among the
background stars of Gemini
the Twins, roughly 10° south-
west of the constellation’s
luminaries, Castor and Pollux.
Although Jupiter’s distance
from Earth continues to grow
this month, the giant planet
remains a fine sight through
any telescope. The disk mea-
sures 37" across the equator
and shows a wealth of atmo-
spheric detail. It’s also fun to
watch the dance of the planet’s
four bright moons. These sat-
ellites change position from
night to night and sometimes
within just a few hours. The
best views come when Jupiter
stands highest late in twilight,
which reduces the blurring
effects from our blanket of air.
The evening sky boasts
another planet that gives Jupi-
ter a run for its money. Mars
reaches opposition and peak
visibility April 8, when it
shines at magnitude –1.5 —
brighter than any star (though
barely in Sirius’ case) and just
shy of mighty Jupiter. The Red
Planet then rises in the east at
sunset and rides highest in the
north around local midnight.
Look for Virgo’s brightest star,
1st-magnitude Spica, just to
Mars’ right as darkness falls.
The planet shines 10 times
brighter than the star.
With its distinctive orange-
red color, Mars is a fine sight
with naked eyes. But the time
around opposition is also the
best for observing through atelescope. Wait until late eve-
ning for the planet to climb
higher and you’ll be rewarded
with fine views of the north
polar cap and dusky surface
markings. The martian disk
measures 15" across, the big-
gest it’s been in more than
six years.
Saturn appears to the
lower right of Mars and tracks
across the sky approximately
two hours after it. The ringed
world lies among the back-
ground stars of Libra the Bal-
ance, where it moves slowly
westward in anticipation of its
own opposition in May. At
magnitude 0.2, the planet
appears noticeably dimmer
than Mars but far brighter than
any of its stellar neighbors.
A telescope shows the
planet’s 18"-diameter disk
surrounded by a beautiful ring
system that spans 42" and tilts
22° to our line of sight. In
moments of steady seeing,
more common once the planet
climbs high after midnight,
the Cassini Division that sepa-
rates the outer A ring from the
brighter B ring shows up
nicely through 10-centimeter
and larger telescopes.
For those who prefer their
observing before dawn,
Venus is an unmistakable
sight in the east. The planet
gleams at magnitude –4.3, far
brighter than any other point
of light in the sky. If you’ve
been following Venus’ appear-
ance through a telescope these
past couple of months, you’ll
notice a smaller and rounder
planet. In mid-April, the inner
world spans 19" and shows a
60-percent-lit disk.Mercury remains on view
in the east before dawn in
early April. Coming off its
best morning appearance of
the year in March, it stands
nearly 10° high an hour before
sunrise. At magnitude –0.2, it
appears conspicuous well to
the lower right of Venus. A
telescope reveals the inner-
most planet’s 6"-diameter disk
and gibbous phase. Mercury
moves closer to our star as the
days go by, however, and it
disappears in the twilight
around midmonth.
A total lunar eclipse
occurs April 15, with totality
visible in its entirety from
most of South America, much
of the Pacific Ocean, and New
Zealand. The partial phases
begin at 5h58m UT and end
at 9h33m UT, with totality
running from 7h07m UT to
8h25mUT. For those in east-
ern Australia, the Moon rises
during totality.
Two weeks later, on April
29, a partial solar eclipse
takes place. Most Australians
get to see the Moon take a bite
from the Sun. From Sydney,
the eclipse begins at 6h14m
UT and reaches a maximum at
sunset, when the Moon covers
52 percent of the Sun’s diam-
eter. The eclipse appears annu-
lar (when the Moon leaves a
ring of sunlight visible) over a
small part of Antarctica.
A 96-percent-lit Moon
occults Saturn on April 17.
Residents of southern South
America can witness the event
in a dark sky. From Santiago,
Chile, Saturn disappears at
7h11m UT and reappears
at 8h25m UT.The starry sky
As a planetarium director, I’m
often asked which bright star
lies closest to the South Celes-
tial Pole. Of course, the
answer depends on what the
questioner means by a “bright
star.” The stars of the South-
ern Cross and the Pointers
(Alpha [α] and Beta [β] Cen-
tauri) offer several good
examples that are circumpolar
south of 33° south latitude.
But one star stands out as
the closest 2nd-magnitude or
brighter star to the pole. It is
Beta Carinae, a magnitude 1.7
star whose proper name is
Miaplacidus. It lies midway
between Canopus and Acrux
and, at a declination of –70°,
a little south of the line that
joins them.
The name Miaplacidus is
still something of a mystery,
but historians think it is a
combination of Arabic
(miyah) and Latin (placidus)
that translates to placid or
calm waters. If so, it’s in keep-
ing with Carina being the keel
of the ship Argo.
Despite the star’s claim to
fame, it doesn’t stand out as
special; it’s not a double or
multiple system, and no
significant deep-sky objects
appear nearby. Like many
naked-eye stars, however,
Miaplacidus is bigger and
brighter than the Sun and will
enjoy a shorter lifetime. It
currently has a core of helium
and likely will start fusing this
element into carbon within
the next few million years. At
that stage it will grow even
more luminous as it becomes
a red giant star.