Astronomy

10°

GEMINI

HYDRA

LEO

CANCER Castor

Regulus

Alphard

Pollux

Eclipsed Moon

January 31, 5:30 A.M. PST

Looking west

A great view of totality (^)
36 ASTRONOMY • JANUARY 2018
Visible to the naked eye
Visible with binoculars
Visible with a telescope
MARTIN RATCLIFFE and ALISTER LING describe the
solar system’s changing landscape as it appears in Earth’s sky.
January 2018: Totality over America
SKYTHIS
MONTH
ll of January’s naked-eye
planets congregate in
the morning sky. Mars
and Jupiter lead the
way, and they provide
the month’s planetary high-
light when they pass within 1°
of each other during the New
Year’s first week. The pair
makes a stunning backdrop
for the Moon when it slides
by a few days later. Mercury
and Saturn also shine brightly
from their positions lower in
the predawn sky.
But the Moon deserves top
billing in January’s sky show.
On the 31st, our satellite dives
completely into Earth’s umbral
shadow, bringing a total lunar
eclipse to viewers in much of
North America, the Pacific
Ocean, Asia, and Australia.
This is the first total eclipse
since September 2015.
on casting its shadow all the
way to its only natural satellite.
Those in the continent’s
western two-thirds can view
at least some of totality, which
gets underway at 6:52 a.m. CST
(4:52 a.m. PST). Totality lasts
76 minutes and can be seen in
its entirety west of a line that
runs from central North
Dakota to New Mexico. The
eclipsed Moon hangs among
the stars of Cancer the Crab
with the Beehive star cluster
(M44) 4° to its northwest.
Observers in Northern
California, Oregon, and
Washington get to witness
the concluding partial phases,
which wrap up at 7:11 a.m. PST.
Fortunately, we don’t have long
to wait for the next total lunar
eclipse. Earth will cast its
shadow on the Moon on July 27
(though this time the eclipse
won’t be visible from North
America), and again the night
of January 20/21, 2019.
The eclipse isn’t Luna’s only
distinction during January.
From North America, the
eclipse occurs before dawn
and delivers better views to
those who live farther west.
East of a line that runs from
the Ohio-Indiana border to
New Orleans, the eclipse
starts after the onset of twi-
light and the Moon sets before
totality begins. The Full
Moon enters Earth’s umbral
shadow at 6:48 a.m. EST
(3:48 a.m. PST). Within
10 minutes, the lunar orb
looks like a giant sugar cookie
with a bite taken out of it.
The geometry of the Sun,
the Moon, and Earth drives
itself home during lunar
eclipses in twilight. With the
Sun just below the eastern
horizon before dawn and the
eclipsed Moon hanging low in
the west, you can almost feel
the giant rock you’re standing
Totality occurs at the month’s
second Full Moon, so it also
earns recognition as a Blue
Moon. Our satellite reaches
its first Full phase on New
Year’s Night. This is the clos-
est Full Moon of 2018, so it is
also the biggest (33.5' across),
and many people will feel
compelled to label it a
“Super Moon.”
Although no planet rises
to the level of “super” this
month, most will reward your
viewing efforts. The evening
sky offers the two outermost
and dimmest members of the
solar system’s family. Despite
their faintness, both Uranus
and Neptune are within range
of binoculars. Neptune lies
lower and should be your first
target. In early January, the
ice giant stands 30° above the
southwestern horizon at the
end of twilight.
Neptune glows at magni-
tude 7.9 among the back-
ground stars of Aquarius.
You can find it near
A
On October 8, 2014, the Full Moon passed into Earth’s umbral shadow and
created this stunning total lunar eclipse. On January 31, observers across
more than half the globe can witness a similar event. DAMIAN PEACH
Viewers in western North America won’t want to miss the spectacular total
lunar eclipse in January 31’s predawn sky. ALL ILLUSTRATIONS: ASTRONOMY: ROEN KELLY