Astronomy - USA (2021-12)

Visible to the naked eye

Visible with binoculars

Visible with a telescope

10°

Jupiter

Saturn

Venus

Mercury

Fomalhaut

Altair

Dec. 28, 30 minutes after sunset

Looking southwest

CAPRICORNUS

PISCIS

AUSTRINUS

AQUARIUS

AQUILA

32 ASTRONOMY • DECEMBER 2021

December’s early-

evening sky offers a

slew of planetary views, begin-

ning with Venus, Saturn, and

Jupiter — all on show soon

after sunset. Capture the top

features of the solar system in

one evening by spotting the

changing phase of Venus; the

spectacular rings of Saturn;

and the remarkably dynamic

jovian atmosphere, its Great

Red Spot, and Jupiter’s four

bright moons.

The first planet to appear

after sunset is Venus, hanging

low in the southwest. It reaches

greatest brilliancy Dec. 4, when

it shines at magnitude –4.9,

easily piercing the bright

twilight. This unmistakable

brilliant jewel lies in eastern

Sagittarius, featuring in

all evening photographic

compositions of the broad

Milky Way.

A waxing crescent Moon,

complete with earthshine, joins

Venus Dec. 6, standing less

than 3° away. As Venus slowly

approaches the Capricornus

border in mid-December, an

interloper, Comet C/2021 A1

(Leonard), might be visible

nearby if it reaches binocular

brightness or better (magnitude

5). Observations of the comet

Dec. 15 and 16 — after it

appears in the evening sky —

will give a good indication

whether or not it will be easily

visible.

On Dec. 17, Leonard stands

5° below Venus. Scan the region

with binoculars for the fuzzy

glow of the comet’s coma. If the

comet is brighter than predic-

tions, it may just reach visibility

to the unaided eye and even

sport a short tail. The comet

remains low in altitude for the

next week, and like all comets,

it will be best recorded in

photographs.

The next day, Venus halts its

easterly trek against the starry

Family portrait (^)
DECEMBER 2021
Venus shines bright
THE SOLAR SYSTEM’S CHANGING LANDSCAPE AS IT APPEARS IN EARTH’S SKY.
BY MARTIN RATCLIFFE AND ALISTER LING
SKY THIS MONTH
Venus reaches greatest brilliancy
early this month as an evening star.
The planet reached the same
magnitude in this 2018 shot as
a morning star. ALAN DYER
By the end of December, four planets are readily visible in the evening sky:
Mercury, Venus, Jupiter, and Saturn. ALL ILLUSTRATIONS: ASTRONOMY: ROEN KELLY