30"CallistoEuropaIoJune 5, 4:30 A.M. EDTJupiterGanymedeWS2°SERPENS
CAUDAOPHIUCHUSENJune 1
5
10
15
2025Rasalhague`f
gdaNGC 6633
Path of Comet PanSTARRSIC 4665M14m3038 ASTRONOMY • JUNE 2022
Skimming the top
COMET SEARCH I K2 is summer’s king
IT’S NICE to have a dependable
7th-magnitude comet on stage
during summer star parties. That’s
bright enough to follow from the
suburbs with a 4- to 6-inch scope.
With binoculars under a country
sky, you can compare the fuzz-
ball to a whole bunch of Messier
globular star clusters.
Comet C/2017 K2 (PanSTARRS)
was discovered May 21, 2017, at a
then-record-breaking distance
beyond Saturn. Astronomers
estimate the nucleus is 25 miles
across, some four times wider than
Halley’s Comet! But PanSTARRS is
not destined to be great because
the closest it gets to the Sun will
be outside Mars’ orbit.
PanSTARRS starts off in binoc-
ular heaven between Aquila and
Ophiuchus during New Moon. The rich Milky Way, split by the Great Rift, is fabulous under a dark sky.
Three nights after the Moon hits Full, jump back into action to watch the fan-shaped tail night by night.
It swings through its edge-on perspective on the 19th, only to next tilt to the other side. Look for a short
green spike peeking out on the south flank, while the sharp white dust tail extends northward. The comet’s
proximity to the sprawling star cluster IC 4665 near Beta (β) Ophiuchi during this transition is a real bonus.Comet C/2017 K2 (PanSTARRS)
located at the eastern end of
Capricornus and ends the
month 1.6° due north of Deneb
Algedi, with the planet glowing
at magnitude 0.5. Saturn
reaches a stationary point
June 5 and begins its retrograde
loop as it approaches opposition
in two months’ time.
Saturn is best viewed in
the hour before dawn, when it
stands more than 30° high in
the south. Its disk spans 17" in
early June and grows barely
perceptibly to 18" by the end of
the month. The stunning rings
are tilted 12° to our line of sight,
the narrowest for the year.
Neptune is in western
Pisces, shining at magnitude 7.8.
It rises after 2 A.M. local time
in early June and soon after
midnight in late June. The easi-
est way to find its approximate
location is to first find Jupiter
and look to the gas giant’s west
to find 4th-magnitude Phi (φ)
Aquarii. Neptune is roughly
midway between the two early
in June. But Jupiter is drifting
eastward, so the gap between
the two planets increases later in
the month. Neptune, too, is
moving eastward against the
background stars; it comes to a
halt June 28 as it turns for its
retrograde loop. This occurs
near a 7th-magnitude field star
0.25° away — the pair will
appear as a close double
through binoculars.Jupiter and Mars rise
together in the eastern sky
June 1, soon after 2:30 A.M. local
time. The stunning pair stands
only 1.8° apart. Jupiter is
brighter at magnitude –2.2,
while Mars shines a rusty
magnitude 0.6. They’re both
in Pisces as well.
When the Last Quarter
Moon enters the vicinity on
June 21, Mars is more than 13.5°east of Jupiter. The Moon stands
some 5° south-southwest of the
gas giant. The following morn-
ing, June 22, the Moon has
drifted east and is 5° from Mars.
Jupiter is up shortly before
1 A.M. local time by the end of
June and stands some 40° high
an hour before dawn. It’s the
planet with the most to offer
telescopic observers: four bright
moons that move in front of and
behind its disk, plus a wealth of
atmospheric details that change
quickly, carried by its less-than-
10-hour rotation period.
Jupiter’s diameter grows from
37" to 41" during June. Its path
carries it into the northwest
corner of Cetus the Whale for
the last six days of the month.
Frequent observers of Jupiter
are aware that in recent years,
the tilt of Callisto’s orbit relative
to our line of sight takes the
moon north and south of the
planet, avoiding the disk. Earlierthis year, Callisto began under-
going occultations, but that
ends again this month. An
intriguing event occurs early on
June 5, when Callisto is partially
hidden behind Jupiter’s north-
ern limb. Observe between
4 A.M. and 5 A.M. EDT to watch
Callisto skim the planet.
Following last month’s con-
junction, the distance between
Mars and Jupiter grows by moreSKY THIS MONTH —Continued from page 33
Early on June 5, Callisto skims the northern limb of Jupiter, just barely dipping
behind the disk.
Comet PanSTARRS flies on a straight path through Ophiuchus this month,
passing near the picturesque star cluster IC 4665.MIDNIGHT
Saturn (east)MORNING SK Y
Mercury (east)
Venus (east)
Mars (east)
Jupiter (east)
Saturn (south)
Uranus (east)
Neptune (southeast)WHEN TO
VIEW THE
PLANETS