2019-08-01_Sky_and_Telescope

44 AUGUST 2019 • SKY & TELESCOPE

Mercury

Saturn

Uranus

Neptune

10 "

Aug 1 11 21 31

116 31

11631

16

16

Venus

Jupiter

Mars

AUGUST 2019 OBSERVING
Planetary Almanac

The Sun and planets are positioned for mid-August; 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.

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.

PLANET VISIBILITY Mercury: visible at dawn from the 3rd to the 26th • Venus: hidden in the

Sun’s glow all month • Mars: hidden in the Sun’s glow all month • Jupiter: visible at dusk, sets near

midnight • Saturn: visible at dusk, sets after midnight

PLANET DISKS have south up, to match the

view in many telescopes. Blue ticks indicate the

pole currently tilted toward Earth.

PEGASUS

CAPRICORNUS

AQUARIUS

Fomalhaut

Rigel

Betelgeuse

MAJORCANIS

PISCES

Sirius

ORION

Pleiades

TAURUS

Pollux

Castor

Procyon

GEMINI Vega

HERCULES

CYGNUS

SCORPIUS

OPHIUCHUS

Antares

SAGITTARIUS

AQUILA

ERIDANUS CETUS

ARIES Arcturus

CORVUS

VIRGO

BOÖTES

LIBRA

LEO

HYDRA

10 am 8 am 6 am 4 am 2 am Midnight 8 pm 6 pm 4 pm 2 pm

+30°

+40°

–10°

–20°

–30°

–40°

+30°

+40°

+20°

–10°

–20°

–30°

–40°

RIGHT ASCENSION

8 h 6 h 4 h 2 h 0 h 22 h 20 h 18 h 16 h 14 h 12 h

DE

CL

IN

AT

IO

N

0° EQUATOR

+10 °

LOCAL TIME OF TRANSIT

10 pm

ECLIPT

IC

0°

Saturn

Uranus

Neptune

Mercury

Jupiter

Venus

Mars

26

Aug

4

7

10

23

20

Aug

14 –15

44 AUGUST 2019 • SKY & TELESCOPE

Date Right Ascension Declination Elongation Magnitude Diameter Illumination Distance

Sun^18 h 42.6m +18 ° 12′ —–26.8^31 ′^31 ′′ —1.015

31 10 h 35.1m +8° 55′ —–26.8 31 ′ 41 ′′ —1.010

Mercury 17 h 39.5m +17 ° 4 0′ 15° Mo +2.0 9.7′′ 13% 0.695

11 8 h 02.9m +19 ° 17′ 19° Mo – 0.2 7.3′′ 44% 0.919

21 9 h 05.6m +17 ° 4 3′ 14° Mo –1.1 5.7′′ 81% 1.173

31 10 h 22.6m +12 ° 0 2′ 4° Mo –1.7 5.0′′ 99% 1.337

Venus^18 h 28.6m +20° 03′ 4° Mo –3.9 9.7′′ 100% 1.728

11 9 h 18.9m +16 ° 5 5′ 2° Mo — 9.6′′ 100% 1.731

21 10 h 07.5m +13° 0 0′ 2° Ev –4.0 9.6′′ 100% 1.729

31 10 h 54.5m +8° 30′ 5° Ev –3.9 9.7′′ 100% 1.721

Mars^19 h 26.4m +16 ° 17′ 11° Ev +1.8 3.5′′ 100% 2.650

16 10 h 03.5m +13° 07′ 6° Ev +1.8 3.5′′ 100% 2.670

31 10 h 39.8m +9° 38′ 1° Ev +1.7 3.5′′ 100% 2.675

Jupiter^116 h 52.5m –22° 05′ 126° Ev –2.4 42.7′′ 99% 4.619

31 16 h 54.2m –22° 14′ 98° Ev –2.2 39.1′′ 99% 5.039

Saturn 119 h 06.6m –22° 16′ 157° Ev +0.2 18.3′′ 100% 9.105

31 19 h 00.3m –22° 29′ 127° Ev +0.3 17.7′′ 100% 9.407

Uranus 16 2 h 16.7m +13° 0 9′ 106° Mo +5.8 3.6′′ 100% 19.528

Neptune^1623 h 16.4m –5° 50′ 155° Mo +7.8 2.4′′ 100% 29.015

August Sun & Planets