2019-06-01+Sky+and+Telescope

46 JUNE 2019 • SKY & TELESCOPE

JUNE 2019 OBSERVING
Sun, Moon & Planets by Fred Schaaf

F

our bright planets adorn the sky

during evening twilight in the lat-

ter half of June. Mars hangs low in the

west-northwest in evening twilight this

month, with much brighter Mercury

passing close by. Jupiter reaches opposi-

tion on June 10th^ and so is visible all

night at its brightest and biggest. Saturn

trails Jupiter by about two hours and

rises as little as 30 minutes after the

Sun sets at month’s end. Venus gives

us a last good look in the brightening

dawn sky before the Morning Star fades

from view in late July.

DUSK

Mars and Mercury are a fascinating

pair in the west-northwest at evening

twilight in June. Mars remains at mag-

nitude 1.8 all month, and the interval

Plentiful Planets

All fi ve bright planets are on display this month — four accompany us

during the evening hours, and one greets us at dawn.

between sunset and Mars-set shrinks

from about 2¼ to 1¼ hours during June.

As Mars appears a little lower at any

given time in dusk with each passing

day, Mercury appears higher. The tiny

world starts the month far below Mars,

setting about 65 minutes after the Sun

but shining at magnitude –1.0. Mercury

fades to magnitude +0.1 by June 17th

when it appears just ¼° from Mars. The

next evening, Mercury is even closer to

Mars. By the 19th, the gap between the

planets has increased to ¾°. On these

dates, Mercury is about half-lit and a bit

more than 7′′ across.

Find Mercury about 6° lower left

of much dimmer Pollux on June 20th

(Mars is the same distance lower left of

Pollux on June 22nd). Mercury reaches

a greatest eastern elongation of 25°

from the Sun on June 23rd. You’ll no

doubt need binoculars near month’s end

to spot Castor and Mars as the latter

moves into a nearly horizontal line with

Mercury (magnitude 1.0 as June ends),

Pollux, and Castor.

DUSK TO DAWN

Jupiter reaches opposition on June

10th and so rules the entire night with

its brilliance and, in telescopes, its size

this month. Throughout June, Jupiter

burns at magnitude –2.6 and its globe

measures about 46′′ wide. This is a little

brighter and bigger than the king of the

planets has been in fi ve years.

The only negative factor in this

month’s (and year’s) display of Jupiter

for observers at mid-northern latitudes

is the extreme southerliness of the

46 JUNE 2019 • SKY & TELESCOPE

To fi nd out what’s

visible in the sky

from your location,

go to skypub.com/

almanac.

Regulus

Denebola

LEO

Moon

June 7

Moon

June 8

Moon

June 9

June 7– 9

Around 10 pm

Looking West, halfway up

10 ° Sickle

Antares

Jupiter

Moon

June 14

Moon

June 15

Moon

June 16

Looking Southeast

Dusk, June 14 –16

1 hour after sunset

SCORPIUS SAGITTARIUS

Saturn

Moon

June 17

Moon

June 18

Looking South-Southeast

June 17–18

Late, toward midnight