SKY_July2014.pdf

SkyandTelescope.com July 2014 49

To see what the sky looks like at any given time and date, go toSkyandTelescope.com/skychart. Fred Schaaf

ORBITS OF THE PLANETS
The curved arrows show each planet’s movement
during July. The outer planets don’t change
position enough in a month to notice at this scale.

Jupiter

Neptune

Uranus

Pluto

Saturn

March

equinox

Sept.

equinox

December

solstice

Mars June solstice Earth

Sun Mercury

Venus

Dawn, July 23 –25

45 minutes before sunrise

Capella

Castor

Pollux

Mercury

Venus

Moon

July 23

Moon

July 24

Moon

July 25

Looking East-Northeast

β Tauri

γ Gem

southwest of 8th-magnitude Ceres in
Virgo around 15h UT on July 5th; see page
50 for details.

ALL NIGHT
Plutoreaches opposition on July 4th and
therefore is highest in the south in the
middle of the night. Even at opposition,
distant Pluto shines only about magnitude
14.1 this year. Observing Pluto requires
dark skies, usually a 10-inch or larger
telescope, and a deep fi nder chart such as
the one on page 50 of the June issue. Pluto
passes near the 5th-magnitude orange star
29 Sagittarii this month.

DAWN
Neptune, in Aquarius, transits the
meridian around the start of morning

twilight this month. Uranus, in Pisces,

transits around sunrise or later. So the

best time to see both of the ice giants is

at dawn’s fi rst gleaming, when they’re as

high as possible. See skypub.com/urnep

for fi nder charts.

Venus rises in the east-northeast

right around the start of astronomical

twilight throughout July. From June 29th

through July 3rd, Venus is less than 5°

above or upper left of Aldebaran. July is

also when the brightest planet dims to

its faintest for the year: –3.8. Its diameter

shrinks slightly, from 12′′ to 11′′, and its

phase grows from 85% to 92% lit, mak-

ing the out-of-roundness of the planet’s

lit part harder to detect — especially in

the unsteady air low in the sky. Even by

sunrise Venus is only 20° high for observ-

ers around 40° north latitude. And next

month its altitude begins to decline.

Mercury puts in a good appearance to

Venus’s lower left for much of July. Mer-

cury is too faint to fi nd early in the month,

but it brightens rapidly and soon moves

higher in morning twilight. The little

planet reaches a greatest western elonga-

tion of 21° on July 12th, but on that date

it’s less than half lit in the telescope and

shines at only magnitude +0.4.

On July 16th Mercury comes closest

in the sky to Venus for this apparition,

just over 6° away. This is an appulse but

not a conjunction — Mercury approaches

Venus and then pulls away again, but

never passes north or south of it. Mercury

appears noticeably lower late in the month

but continues to brighten, up to magni-

tude –1.4 at month’s end.

MOON PASSAGES

The Moon is a waxing crescent lower left

of Regulus on July 1st. On the 5th, the

fi rst-quarter Moon hangs close to Spica

and Mars for North American observers. It

actually occults Mars as seen from much

of Latin America at night or dusk, and in

Hawaii during daylight. On July 7th the

Moon occults Saturn for southernmost

South America and appears close to

Saturn for North American observers. The

waning crescent is very near Aldebaran on

July 22nd, and it’s rather close to the right

of Venus and Mercury on July 24th and

25th, respectively.

EARTH

Earth is at aphelion (farthest from the

Sun in space for the year, 94,506,000

miles) at 8 p.m. EDT on July 3rd.✦