46 AUSTRALIAN SKY & TELESCOPEAPRIL 2016
Sun, Moon and Planets
Red sky at night –
Mars versus Antares
Planet takes on star in this battle of the celestial heavyweights.
T
he days are becoming shorter
andwinterisfastonthe
way, bringing the delicious
anticipation of longer nights of
crisp air, clear skies and plenty of
time for stargazing.
The innermost planet, Mercury,
is essentially out of action during
April, being very, very low (only
afewdegreesaltitude)onthe
western horizon. We’ll have to wait
for the morning skies of late May
to get a good view of it again. May
will also see a transit of Mercury
acrossthefaceoftheSun,butalas,
wehereinAustralasiawillmissit
–it’lloccurduringournight-time,
and those on the other side of the
Earth will have the box seat.
VenusstartsAprillowinthe
eastern sky before dawn, slowly
getting even lower as the weeks
progress until it becomes lost in the
Sun’sglare.JustaswithMercury,
we’regoingtohavetowaitawhileuntilVenusreturns–mid-Julyin
fact, but from then on we’ll have a
greatviewofit outtothewestafter
sunset for the rest of the year.
As the title of this month’s
column suggests, Mars is the planet
of the month at the moment. April
will begin with the Red Planet
rising in the east, not far on the
sky from the star Alpha Scorpii,
or Antares. As you might know,
the name Antares means ‘rival of
Mars’,andwhenyouseethetwo
of them close together, it’s easy
toseewhythenamehasstuck—
bothorbsshinewitharuddy,red
colour,althoughMarsisquiteabit
brighter.Theringedplanet,Saturn,
will join Mars and the Moon on
April25toformaneattriangle
(seethediagram)—it’llbeagreat
occasion for some astrophotography
if you feel so inclined.
Marswillreachoppositionon
April 22, and its closest point toJONATHAN NALLY Earth on May 30. See the article
on pages 58-60 for more details
on how to observe the Red Planet
during this apparition.
Jupiter has only just passed
opposition. The giant planet will rise
in the east shortly after sunset and
ride high for most of the night. Watch
for the Moon nearby on April 18. As
you will have read elsewhere in this
issue, Jupiter’s Great Red Spot (GRS)
seems to be shrinking. If you want to
see for yourself, check out the table of
dates and times on page 50 for when
the GRS will be visible to you.
Saturn is getting closer to
opposition (which will come in
June), rising around 8pm in the
middle of April. The sixth planet
fromtheSunisagreattargetfor
evenasmalltelescope—ifyou
have access to one, turn it towards
Saturn and prepare to be rewarded
with a breathtaking view of the
planetandit’srings.Andwatchfor
theMoonclosebyonthe25thtoo
(see the diagram).✦Venus and the
crescent Moon
will be low on the
eastern horizon
before dawn at the
beginning of April.
Mars and the star Antares (a name which means ‘rival of Mars’)
will make a fine pair in the evening sky, with Saturn nearby.