Astronomy

Pluto aims for a slice of Pi
E
June 22
24
N
26
SAGITTARIUS
Path of Pluto
28
30
0.02°
Everyone’s favorite dwarf planet passes a hairbreadth south of magnitude
2.9 Pi (π) Sagittarii during June’s final week.
best time to look for it is when
it lies near greatest elongation,
as it conveniently does the
night of opposition.
Late June is a great time to
hunt for Pluto because it passes
close to a 3rd-magnitude star
that will guide you right to
the spot. Thanks to the New
Horizons spacecraft, which
flew past in July 2015, this dim
dot has now been revealed as
an active world of diverse surface
features.
So view Pluto with new eyes
when it stands 2.7' due south of
Pi (π) Sagittarii on the evening
of June 26. You’ll find Pi in
northeastern Sagittarius, north
of the handle of that constellation’s
Teapot asterism. At magnitude
14.1, Pluto is certainly a
challenging object, barely visible
through an 8-inch scope
under a clear dark sky. Many
stars of similar brightness lurk
in the area, so use a detailed
star chart like the one above.
Sketch or image the field on
consecutive nights and you
should be able to identify Pluto
as the object that moved.
You’ll have to wait until
after midnight to target the
next planet. Neptune rises
around 2 a.m. local daylight
time June 1 and some two
hours earlier by month’s end.
It nestles comfortably next to
4th-magnitude Lambda (λ)
Aquarii. Swing 7x50 binoculars
to this star in eastern
Aquarius and you’ll spot magnitude
7.9 Neptune in the
same field of view, just 0.5°
to the southeast. The distant
planet remains there all
month because it reaches its
stationary point June 14.
A telescope nicely shows
Neptune’s distinct blue-gray
color. At magnifications of
150x or more, you’ll see a
2.3"-diameter disk that confirms
it as a planet.
Uranus rises after 3 a.m.
local daylight time June 1, but
it barely climbs a few degrees
high before twilight starts to
interfere. You’ll be better off
waiting until late in the month
to track it down. On the 30th,
the planet stands nearly 25°
high in the east as dawn starts
to paint the sky. It lies in a
sparse region of Pisces, some
4° west of 4th-magnitude
Omicron (ο) Piscium. Don’t
confuse magnitude 5.9 Uranus
with a handful of similarly
bright stars nearby. Although
you can see the planet quite
easily through binoculars,
you’ll likely need a telescope
to confirm a sighting. Only
Uranus shows a disk, which
spans 3.4" and glows distinctly
blue-green.
Once morning twilight is
well underway, you can start
searching for Mercury. The
innermost planet reaches
LOCATINGASTEROIDS
The Lion gives way to the Maiden
The pickings are pretty slim for
asteroid aficionados in June. To
achieve success during the early
evening hours, rock hounds will
have to push their skills and
perseverance. As luck would
have it, only two asteroids —
7 Iris and 8 Flora — shine as
bright as 10th magnitude, and
both lie in front of the Milky
Way’s center. Slightly fainter
10 Hygeia proves less difficult to
spot because it resides against
the galaxy’s outer fringes near
the Leo-Virgo border.
Take care when jumping to
4th-magnitude Upsilon (υ)
Leonis. Although this is the
brightest star on the chart
Hygeia slides from Leo into Virgo
VIRGO
E
1°
July 1
26
Path of Hygeia
21
greatest elongation June 5,
when it lies 24° west of the Sun
and appears 6° high in the east
a half-hour before sunrise. It
then shines at magnitude 0.5
and shows up clearly through
binoculars. But the planet’s
visibility actually improves a
bit in the next couple of weeks
as it maintains its predawn
altitude but grows brighter. On
the 15th, Mercury shines at
magnitude –0.3, bright enough
GET DAILY UPDATES ON YOUR NIGHT SKY AT www.Astronomy.com/skythisweek.
N
below, it’s easy to land on a different
star when observing from
the suburbs or under bright
moonlight. Just because you
see a pinpoint near Hygeia’s
expected position, it doesn’t
mean you have acquired the target.
The surefire way to confirm
a sighting is to sketch the field
with a handful of stars. Come
back a night or two later to see
which dot has changed position.
With a diameter of 275 miles,
Hygeia is the fourth-largest
object in the asteroid belt.
Astronomers discovered nine
others before this one because
it is so dark, reflecting 7 percent
of the sunlight hitting it.
16
87
LEO
11
6
June 1
You’ll need patience to locate the fourth-largest asteroid because it
glows around 11th magnitude. Look for it 1° south of Upsilon (υ) Leonis
on June 21 and 22.
to see with the naked eye
under a haze-free sky. When
viewed through a telescope at
midmonth, the planet appears
7" across and slightly more
than half illuminated.
Venus remains out of sight
all month. It passes on the
Sun’s far side from our viewpoint,
a configuration known
as superior conjunction, on
June 6. It will reappear in the
evening sky in late July.
WWW.ASTRONOMY.COM 43