Sky & Telescope - January 2020 - 44

JANUARY 2020 OBSERVING
Planetary Almanac

PLANET VISIBILITY Mercury: very low at dusk starting on the 27th * Venus: visible at dusk,
sets in early evening * Mars: visible at dawn * Jupiter: very low at dawn starting on the 12th *
Saturn: hidden in the Sun's glow all month

Mercury

11

31

21

January Sun & Planets

Venus

Date

Declination

Elongation

Magnitude

Diameter

Illumination

Distance

1

18h

42.4m

-23° 05′

-

-26.8

32′ 32″

-

0.983

31

20h

50.9m

-17° 40′

-

-26.8

32′ 28″

-

0.985

1

18h 18.1m

-24° 39′

6° Mo

-0.9

4.7″

99%

1.434

11

19h 28.5m

-23° 51′

2° Ev

-1.4

4.7″

100%

1.429

21

20h 39.4m

-20° 33′

7° Ev

-1.2

4.9″

98%

1.362

31

21h

47.3m

-14° 46′

14° Ev

-1.0

5.5″

87%

1.212

1

21h

08.7m

-18° 21′

34° Ev

-4.0

13.1″

82%

1.278

11

21h 56.7m

-14° 19′

36° Ev

-4.0

13.7″

80%

1.220

21

22h 42.5m

-9° 40′

38° Ev

-4.0

14.4″

77%

1.160

31

23h

26.4m

-4° 38′

40° Ev

-4.1

15.2″

74%

1.096

1

15h

43.8m

-19° 23′

42° Mo

+1.6

4.3″

96%

2.184

16

16h

26.1m

-21° 29′

47° Mo

+1.5

4.5″

95%

2.073

31

17h 09.7m

-22° 55′

52° Mo

+1.4

4.8″

93%

1.956

1

18h 27.9m

-23° 12′

3° Mo

-1.8

31.8″

100%

6.209

31

18h 57.3m

-22° 45′

27° Mo

-1.9

32.5″

100%

6.074

1

19h

31.3m

-21° 44′

11° Ev

+0.5

15.1″

100%

10.996

31

19h

46.3m

-21° 10′

16° Mo

+0.6

15.1″

100%

10.976

Uranus

16

2h 01.5m

+11° 51′

97° Ev

+5.8

3.6″

100%

19.667

Neptune

16

23h 11.3m

-6° 20′

51° Ev

+7.9

2.2″

100%

30.538

Sun

1

16

Mercury

31
Mars

1

16

31

Jupiter

Venus

Mars
16
Saturn

Jupiter

Saturn
16
Uranus

Neptune

The table above gives each object's right ascension and declination (equinox 2000.0) at 0h Universal Time on selected dates,
and its elongation from the Sun in the morning (Mo) or evening (Ev) sky. Next are the visual magnitude and equatorial diameter.
(Saturn's ring extent is 2.27 times its equatorial diameter.) Last are the percentage of a planet's disk illuminated by the Sun and
the distance from Earth in astronomical units. (Based on the mean Earth-Sun distance, 1 a.u. is 149,597,871 kilometers, or
92,955,807 international miles.) For other dates, see skyandtelescope.com/almanac.

10"

PLANET DISKS have south up, to match the
view in many telescopes. Blue ticks indicate the
pole currently tilted toward Earth.

18h

+40°

16h

14h
12h
R I GH T AS C EN S I O N

Vega

14

+10°

Regulus

AQUILA

VIRGO

OPHIUCHUS

0°
-10°

Saturn
Jupiter

Mars

CANCER

17

LIBRA

EC

20

8h
Castor
Pollux

6h

4h

2h

Pleiades

10 am

+40°
CYGNUS

ARIES

Spica

LIP

TI

6
Betelgeuse

C

PEGASUS

Uranus

TAURUS

Jan 2

Procyon
EQUATOR

ORION

Neptune

29

+30°
+20°
+10°

HYDRA

-10°

Venus

CETUS
ERIDANUS

CAPRICORNUS

CANIS
MAJOR

Mercury
-30°

Fomalhaut

8 am

6 am

4 am

2 am

Midnight

10 pm

8 pm

LOCAL TIME OF TRANSIT
6 pm
4 pm

2 pm

The Sun and planets are positioned for mid-January; the colored arrows show the motion of each during the month. The Moon is plotted for evening dates in the Americas when it's waxing (right side
illuminated) or full, and for morning dates when it's waning (left side). "Local time of transit" tells when (in Local Mean Time) objects cross the meridian - that is, when they appear due south and at
their highest - at mid-month. Transits occur an hour later on the 1st, and an hour earlier at month's end.

44

JANUARY 2 02 0 * SK Y & TELESCOPE

0°

AQUARIUS

Rigel
Sirius

CORVUS

SCORPIUS

-40°

22h

PISCES

Jan
10 -11

Antares

SAGITTARIUS

0h

GEMINI

LEO

Arcturus

HERCULES

+20°

-30°

10h

BOÖTES

+30°

Right Ascension

DE C LIN AT ION

Jan 1

-40°
http://www.skyandtelescope.com/almanac
Sky & Telescope - January 2020

Table of Contents for the Digital Edition of Sky & Telescope - January 2020
