Astronomy

PATHOF THE

PLANETS

The planets

in the sky

These illustrations show the size, phase, and orientation of each planet and the two brightest dwarf planets at 0h UT

for the dates in the data table at bottom. South is at the top to match the view through a telescope.

The planets in January 2018

AUR

ORI

COL

LEP

SCT

AQL

LY R

CYG

VUL

DEL SGE

LY N

CNC

PYX PUP

VEL

ANT

CRT

HYA

SEX

LEO

SCO

OPH

HER

DRA

CRV

COM

BOÖ

SER

VIR

LIB

LUP

TEL

SGR

EQU

AQR

CAP

MIC

CrB

CVn

CMi

CMA

Objects visible before dawn UMa

PPaatthh ooff tthhee

Celestial equator

Sun

Moon phases Dawn Midnight

Pluto

Saturn

Jupiter

Mercury appears bright

before dawn in early January

Vesta

Mars

Asteroid Flora reaches

opposition January 2

A total lunar eclipse occurs

January 31 across most of

North America, Australia,

and Asia.

Dwarf planet Ceres reaches

opposition January 31

Massalia

Mars passes 0.2° south

of Jupiter on January 6/7

18 17 16 15 14 13 12 11 78910 6 5 4 3 2 1

31 30 29

Venus

Mars

Mercury

Ceres

Uranus

Saturn

Neptune

Pluto

10"

S

WE

N

Jupiter

40 ASTRONOMY • JANUARY 2018

Planets MERCURY VENUS MARS CERES JUPITER SATURN URANUS NEPTUNE PLUTO

Date Jan. 1 Jan. 15 Jan. 15 Jan. 15 Jan. 15 Jan. 15 Jan. 15 Jan. 15 Jan. 15

Magnitude –0.3 –4.0 1.4 7.1 –1.9 0.5 5.8 7.9 14.3

Angular size 6.7" 9.8" 5.1" 0.8" 34.2" 15.1" 3.5" 2.2" 0.1"

Illumination 62% 100% 92% 99% 99% 100% 100% 100% 100%

Distance (AU) from Earth 0.999 1.711 1.830 1.645 5.761 10.972 19.879 30.601 34.464

Distance (AU) from Sun 0.389 0.728 1.619 2.576 5.430 10.065 19.901 29.945 33.485

Right ascension (2000.0) 17h07.4m 19h52.3m 15h21.8m 9h26.0m 15h06.9m 18h11.9m 1h31.2m 22h55.0m 19h22.1m

Declination (2000.0) –20°52' –21°54' –17°39' 28°00' –16°24' –22°31' 8°56' –7°54' –21°40'