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February a great month for sky watchers |
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February 1, 2017 |
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| By Predrag
Agatonovic |
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By Bruce McClure and Deborah Byrd
Earthsky.org
As February 2017 opens, the young moon is
sweeping past the planets Venus and Mars in the
western sky after sunset. Venus rules over the
evening sky while Jupiter lords over the morning
sky. Venus, the brightest planet, blazes in the
west first thing at dusk, and showcases its
greatest illuminated extent on February 17.
Jupiter, the second-brightest planet, lights up
the nighttime between late evening and sunrise.
Mars is near Venus in the evening sky, but it’s
higher up and much fainter than Venus, setting
in the west shortly after Venus does around
mid-evening. Meanwhile, Saturn appears in the
southeastern sky during the predawn hours.
Mercury is falling into the glare of the rising
sun.
Brilliant Venus is the “evening star.” Okay,
it’s not a star. It’s a planet. But people will
call it the evening star all the same. In these
past weeks, many have noticed Venus and been
amazed at its brilliance in the west after
sunset. It’s the brightest planet and very, very
bright, and will display its greatest brilliancy
as the evening “star” on or near February 17.
Be sure to catch the waxing crescent moon near
Venus on February 1, and then again on February
28.
Venus and Mars remain fairly close together on
the sky’s dome throughout February 2017. But
brilliant Venus is brightening whereas
modestly-bright Mars is dimming. By mid-month,
Venus will outshine Mars by over 200 times. When
the month of March comes rolling along, Venus
will quickly fall downward from Mars, and toward
the sunset. Venus will meet up with the setting
sun, to transition from the evening to the
morning sky, on March 25. Although Mars won’t
meet up with the setting sun until late July
2017, Mars will dim all the more between now and
then, and moreover, will spend a few months
obscured in evening twilight.
From mid-northern latitudes (U.S. and Europe),
Venus sets about four hours after the sun in
early February and about three hours after the
sun by the month’s end.
At mid-southern latitudes (Australia and South
Africa), Venus sets about about two hours after
the sun in early February and about one hour
after sun by the month’s end.
Next month, in March 2017, it may be possible to
see Venus as both the evening “star” and morning
“star” for a few to several days, starting on or
near March 20. Look in the west shortly after
sunset to see Venus at dusk, and look east
shortly before sunrise to view Venus at dawn.
Click here for an almanac giving you the setting
time and rising time of Venus in your sky.\
Mars, east of Venus, until mid-evening. After
appearing as a bright red light in our sky last
May and June 2016, Mars now appears only
modestly bright (though possibly still ruddy),
above dazzling Venus. Venus is so bright that it
pops out almost immediately after sunset, but
you’ll have to wait until nightfall to see
fainter Mars. Look for the moon close to Mars
for a few evenings, centered on February 1 and
again on February 28.
From mid-northern latitudes (U.S. and Europe),
look for the red planet Mars to set in the west
around 9 to 10 p.m. all month long.
At mid-southern latitudes (Australia and South
Africa), Mars sets in the west around 2.5 hours
after the sun in early February and about two
hours after sundown by the month’s end.
Mars will linger in our sky for several more
months. Keep in mind, however, that Earth is
traveling away from Mars as we speak – moving
far ahead of this planet in the endless race
around the sun – so Mars is dimming in our
evening sky. Mars is in its long, lingering,
relatively inconspicuous phase now. It’ll be
still visible in the west to the unaided eye –
though not prominent – during its conjunction
with Uranus on February 27, 2017.
Mars won’t make its transition from the evening
to morning sky until July 27, 2017. Even so,
Mars’ stature in the evening sky will continue
to diminish to that of a rather faint “star,”
and we expect few – if any – skywatchers to
observe the conjunction of Mars and Mercury in
the evening sky on June 28, 2017.
The conjunction of Mars and Venus in the morning
sky on October 5, 2017, may well present the
first good opportunity to spot Mars in the
morning sky when it returns from being behind
the sun on July 27, 2017.
Saturn swung behind the sun on December 10,
2016, transitioning from the evening to morning
sky.
In both the Northern and Southern Hemispheres,
Saturn is easy to view in the predawn hours
throughout February 2017. From mid-northern
latitudes, Saturn rises in the east about three
hours before the sun in early February, and by
the month’s end, Saturn comes up four hours
before sunrise.
At temperate latitudes in the Southern
Hemisphere, Saturn rises about four hours before
the sun in early February, and by the month’s
end, Saturn rises around midnight.
Be sure to let the waning crescent moon guide
you to Saturn (and the nearby star Antares) for
several days, centered on or near February 20.
Saturn, the farthest world that you can easily
view with the eye alone, appears golden in
color. It shines with a steady light.
Binoculars don’t reveal Saturn’s gorgeous rings,
by the way, although binoculars will enhance
Saturn’s golden color. To see the rings, you
need a small telescope. A telescope will also
reveal one or more of Saturn’s many moons, most
notably Titan.
Saturn’s rings are inclined at nearly 27-degrees
from edge-on, exhibiting their northern face. In
October 2017, the rings will open most widely,
displaying a maximum inclination of 27-degrees.
As with so much in space (and on Earth), the
appearance of Saturn’s rings from Earth is
cyclical. In the year 2025, the rings will
appear edge-on as seen from Earth. After that,
we’ll begin to see the south side of Saturn’s
rings, to increase to a maximum inclination of
27-degrees by May 2032.
Jupiter’s prominence as the “morning star” will
be hard to overlook.
Seek out the brightest starlike object in the
predawn sky or the morning twilight and that’ll
be the king planet Jupiter! If you stay up till
late evening, you might even catch Jupiter
rising above your eastern horizon before your
bedtime.
From mid-northern latitudes, like those in the
U.S. and Europe, Jupiter rises roughly one hour
before the midnight hour in early February. By
the month’s end, Jupiter rises around 10 p.m.
From mid-southern latitudes (Australia), look
for Jupiter to rise around mid-to-late evening
in early February and early-to-mid evening by
the end of the month.
If you’re not a night owl, your best bet for
catching Jupiter is to wake up before sunrise to
see this brilliant beauty of a planet lighting
up the predawn and dawn sky. Watch for the
waning moon to join up with Jupiter for several
days, centered on or near February 15. See the
above sky chart.
By the way, Jupiter shines in front of the
constellation Virgo, near Virgo’s brightest
star, Spica. Jupiter serves a great reference
for learning the constellations of the zodiac,
because Jupiter stays in each constellation for
roughly a year. So use Jupiter to become
familiar with the star Spica and the
constellation Virgo, starting now, and
throughout 2017.
If you have binoculars or a telescope, it’s
fairly easy to see Jupiter’s four major moons,
which look like pinpricks of light on or near
the same plane. They are often called the
Galilean moons to honor Galileo, who discovered
these great Jovian moons in 1610. In their order
from Jupiter, these moons are Io, Europa,
Ganymede and Callisto.
These moons circle Jupiter around the Jovian
equator. In cycles of six years, we view
Jupiter’s equator edge-on. So, in 2015, we got
to view a number of mutual events involving
Jupiter’s moons through a high-powered
telescope. Click here or here or here for more
details.
Although Jupiter’s axial tilt is only three
degrees out of perpendicular relative to the
ecliptic, Jupiter’s axis will tilt enough toward
the sun and Earth so that the farthest of these
four moons, Callisto, will NOT pass in front of
Jupiter or behind Jupiter for a period of about
three years, starting in late 2016. During this
approximate three-year period, Callisto will
remain “perpetually” visible, alternately
swinging “above” and “below” Jupiter.
Nominally, Mercury remains in the morning sky
all month long, though it also sinks closer to
the glare of sunrise daily. From either the
Northern Hemisphere or the Southern Hemisphere,
your best chance of catching Mercury is during
the early part of the month, when Mercury rises
a maximum time before sunrise. But Mercury will
be better positioned for viewing from the
Southern Hemisphere.
Mercury is tricky. If you look too soon, Mercury
will still be under the horizon; if you look too
late, it will be obscured in the haze of morning
twilight.
Watch for Mercury low in the sky, and near the
sunrise point on the horizon, seeking for this
hidden treasure around 60 to 45 minutes before
sunrise. Saturn rises before Mercury does, so
use Saturn as your guide “star” to locating
Mercury closer to the horizon.
Remember, binoculars are always helpful for any
Mercury search. Good Luck!
Mercury will transition from the morning to
evening sky on March 7.
For the Northern Hemisphere, Mercury will put on
a good showing in the evening sky for several
weeks, centered on April 1.
By bright planet, we mean any solar system
planet that is easily visible without an optical
aid and that has been watched by our ancestors
since time immemorial. In their outward order
from the sun, the five bright planets are
Mercury, Venus, Mars, Jupiter and Saturn. These
planets actually do appear bright in our sky.
They are typically as bright as – or brighter
than – the brightest stars. Plus, these
relatively nearby worlds tend to shine with a
steadier light than the distant, twinkling
stars. You can spot them, and come to know them
as faithful friends, if you try.
In February 2017, two of the five bright planets
appear in the evening sky at dusk/nightfall:
Venus and Mars. Jupiter is out from late evening
till dawn, whereas Saturn and Mercury are found
exclusively in the morning sky. |
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