Jupiter, Mars, the Lyrid meteor shower and 2016’s best views of Mercury are all visible in the sky this month.
Jupiter,
where our Juno mission will begin orbiting on July 4, continues to
shine almost as brightly this month as last. And eagle-eyed telescope
viewers will see a transit, a shadow transit, an occultation and an
eclipse of Jupiter’s moons- all in one night: April 6-7.
Io transits first, crossing the planet beginning at 9:52 p.m. EDT. It’s shadow can be seen less than an hour later.
Next
Jupiter occults, or eclipses, Europa as Europa slips behind the giant
planet at 10:48 p.m. EDT. At 3 a.m. Europa reappears from its eclipse,
dramatically leaving the shadow of Jupiter.
Ganymede transits the planet beginning at 1:01 EDT April 7.
Check
out the other planets in April, too! Mercury is always a challenging
object to view, but this month you can spot it after sunset about 10
degrees above the horizon. Through a telescope you can see its phase. It
will appear like a tiny crescent moon, with about 1/3 of its disk
illuminated.
Mars
is finally visible before midnight this month. It rises in the
southeast at about 10 p.m. by the end of April. The best observing of
Mars will be when it is highest in the sky. This means a few hours
before dawn. Its brightness and apparent size increase dramatically this
month. By month’s end, Mars appears nearly twice as bright as at the
beginning of the month.
About
mid-month you’ll see Mars near its rival in the sky: the
similar-colored red supergiant star Antares. The name “Antares” means
“equal to or rival of Mars”.
Earth
moves almost twice as fast as Mars does, so it often passes Mars in
their race around the sun. This causes “retrograde motion”: an illusion
we see from our viewpoint on Earth.
Retrograde
motion happens as Earth catches up to Mars, causing Mars to appear slow
to slow its eastward motion against the stars. After a few days, when
Earth has overtaken Mars, the Red Planet seems to move westward.
Eventually, Earth moves far enough around its orbit that Mars appears to
be moving eastward again.
April
features one meteor shower, the Lyrids. This year the Lyrids are marred
by the full moon.
The best time to view will be just before dawn on April 23, when the constellation Lyra is overhead and the moon will be
near to setting.
With all of these great things to spot in the sky this month, be sure to get outside and look up!
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