Sky and Telescope - January 2018 - 47
* To find out what's visible in the sky
from your location, go to skypub.com/
almanac.
December
solstice
Earth
On the morning of January 6th,
Jupiter is resplendent with Mars immediately to the right and the 2.6-magnitude wide double star Alpha (α) Librae
(Zubenelgenubi) some 2° to the planets'
upper right. Mars-colored Antares flickers marginally into view early during
twilight in the southeast, more than 20°
to the lower left of the Jupiter and Mars
pair. As the month progresses the two
planets move away from Alpha Librae,
and Mars retreats from Jupiter while
advancing upon climbing Antares. Mars
passes north of Antares February 6th-
10th, and in July it will reach its best
opposition since 2003, shining at magnitude -2.8 and looming about 5 times
wider than at present in telescopes.
By the end of January, Jupiter rises
as early as 1:30 a.m. local time, Mars
at about 2:30 a.m., and both reach the
meridian in morning twilight.
DAW N
Mercury and Saturn form the second planetary pair in the first half of
January, but much lower on the eastern
horizon. Mercury shines at magnitude
-0.3 as it reaches greatest elongation of
23° west from the Sun on New Year's
Day, and we'll be able to witness this
fine apparition for a few more weeks
before the planet appears too low in the
Uranus
Mercury
Saturn
Venus
The curved arrows show each planet's movement during January. The outer planets don't
change position enough in a month to notice at this scale.
morning twilight. In contrast, magnitude-0.5 Saturn remains elusive during
the year's first week but climbs progressively higher throughout the month.
On January 13th, at their closest,
Mercury and Saturn shine only 0.6°
apart. Mercury's gibbous globe is then
little more than 5″ across, not much
more than 1/3 the apparent diameter of
Saturn's globe, but it will exhibit much
greater surface brightness. Don't expect a
very sharp view of either planet, however,
for the two are still low in the southeast
even 30 minutes before sunrise. In fact, it
may be a challenge spotting Saturn with
the naked eye at any point that morning.
The situation will be quite different by
month's end when Saturn rises well over
2 hours before the Sun.
Jan 26 -27
Around 8 pm
TA U R U S
Pleiades
Moon
Jan 27
Saturn
Aldebaran
Moon
Jan 26
Mercury
Looking Southeast
Mars
ORBITS OF THE PLANETS
30 minutes before sunrise
Antares
Neptune
Sun
June
solstice
Dawn, Jan 13
Moon
Jan 13
Sept.
equinox
March
equinox
Jupiter
Looking South, high in the sky
E A R TH A N D M O O N
Earth reaches perihelion, its closest
approach to the Sun in its orbital path
through space, at 5:35 UT on January
3rd, when it is 98.3% of its average
distance from the Sun.
The Moon is full (for the first time
this month) on the North American evening of January 1st - and
will appear slightly larger than usual
because it will be only about 4 hours
past perigee (when it's at its nearest
point in its orbit around the Earth). The
Moon then brushes past Regulus in Leo
on the left in the middle of the night
of January 4-5 (an occultation will be
visible throughout parts of northern
Canada and Alaska).
The waning crescent Moon forms a
beautifully compact triangle with the
gas giant Jupiter and rocky Mars before
dawn on January 11th. Very low in the
southeast, a much thinner lunar sliver
is just over 6° above Saturn on January 14th and some 4° left of Mercury
on January 15th. On January 31st the
Moon is full for a second time in the
calendar month for observers in North
America, and all but the eastern part of
the continent can witness that Moon
totally eclipsed (see p. 48 for more
details of this event).
¢ FRED SCHAAF founded "Dark Skies
for Comet Halley" and wrote the bill proposing the New Jersey Light Pollution
Study Commission, both in the 1980s.
sk yandtelescope.com * JA N UA RY 2 018
47
http://www.skypub.com/almanac
http://www.skypub.com/almanac
http://www.skyandtelescope.com/
Sky and Telescope - January 2018
Table of Contents for the Digital Edition of Sky and Telescope - January 2018
Contents
Sky and Telescope - January 2018 - Cover1
Sky and Telescope - January 2018 - Cover2
Sky and Telescope - January 2018 - 1
Sky and Telescope - January 2018 - Contents
Sky and Telescope - January 2018 - 3
Sky and Telescope - January 2018 - 4
Sky and Telescope - January 2018 - 5
Sky and Telescope - January 2018 - 6
Sky and Telescope - January 2018 - 7
Sky and Telescope - January 2018 - 8
Sky and Telescope - January 2018 - 9
Sky and Telescope - January 2018 - 10
Sky and Telescope - January 2018 - 11
Sky and Telescope - January 2018 - 12
Sky and Telescope - January 2018 - 13
Sky and Telescope - January 2018 - 14
Sky and Telescope - January 2018 - 15
Sky and Telescope - January 2018 - 16
Sky and Telescope - January 2018 - 17
Sky and Telescope - January 2018 - 18
Sky and Telescope - January 2018 - 19
Sky and Telescope - January 2018 - 20
Sky and Telescope - January 2018 - 21
Sky and Telescope - January 2018 - 22
Sky and Telescope - January 2018 - 23
Sky and Telescope - January 2018 - 24
Sky and Telescope - January 2018 - 25
Sky and Telescope - January 2018 - 26
Sky and Telescope - January 2018 - 27
Sky and Telescope - January 2018 - 28
Sky and Telescope - January 2018 - 29
Sky and Telescope - January 2018 - 30
Sky and Telescope - January 2018 - 31
Sky and Telescope - January 2018 - 32
Sky and Telescope - January 2018 - 33
Sky and Telescope - January 2018 - 34
Sky and Telescope - January 2018 - 35
Sky and Telescope - January 2018 - 36
Sky and Telescope - January 2018 - 37
Sky and Telescope - January 2018 - 38
Sky and Telescope - January 2018 - 39
Sky and Telescope - January 2018 - 40
Sky and Telescope - January 2018 - 41
Sky and Telescope - January 2018 - 42
Sky and Telescope - January 2018 - 43
Sky and Telescope - January 2018 - 44
Sky and Telescope - January 2018 - 45
Sky and Telescope - January 2018 - 46
Sky and Telescope - January 2018 - 47
Sky and Telescope - January 2018 - 48
Sky and Telescope - January 2018 - 49
Sky and Telescope - January 2018 - 50
Sky and Telescope - January 2018 - 51
Sky and Telescope - January 2018 - 52
Sky and Telescope - January 2018 - 53
Sky and Telescope - January 2018 - 54
Sky and Telescope - January 2018 - 55
Sky and Telescope - January 2018 - 56
Sky and Telescope - January 2018 - 57
Sky and Telescope - January 2018 - 58
Sky and Telescope - January 2018 - 59
Sky and Telescope - January 2018 - 60
Sky and Telescope - January 2018 - 61
Sky and Telescope - January 2018 - 62
Sky and Telescope - January 2018 - 63
Sky and Telescope - January 2018 - 64
Sky and Telescope - January 2018 - 65
Sky and Telescope - January 2018 - 66
Sky and Telescope - January 2018 - 67
Sky and Telescope - January 2018 - 68
Sky and Telescope - January 2018 - 69
Sky and Telescope - January 2018 - 70
Sky and Telescope - January 2018 - 71
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Sky and Telescope - January 2018 - 73
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Sky and Telescope - January 2018 - 75
Sky and Telescope - January 2018 - 76
Sky and Telescope - January 2018 - 77
Sky and Telescope - January 2018 - 78
Sky and Telescope - January 2018 - 79
Sky and Telescope - January 2018 - 80
Sky and Telescope - January 2018 - 81
Sky and Telescope - January 2018 - 82
Sky and Telescope - January 2018 - 83
Sky and Telescope - January 2018 - 84
Sky and Telescope - January 2018 - Cover3
Sky and Telescope - January 2018 - Cover4
Sky and Telescope - January 2018 - SGA18SAL
Sky and Telescope - January 2018 - 90
Sky and Telescope - January 2018 - SGA18S
Sky and Telescope - January 2018 - SGA18SA
Sky and Telescope - January 2018 - SGA18EAL
Sky and Telescope - January 2018 - 94
Sky and Telescope - January 2018 - SGA18E
Sky and Telescope - January 2018 - SGA18EA
Sky and Telescope - January 2018 - SGA18RAL
Sky and Telescope - January 2018 - 98
Sky and Telescope - January 2018 - SGA18R
Sky and Telescope - January 2018 - SGA18RA
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