WHEN TO
VIEW THE
PLANETS
August 22, 3 A.M. EDT 30"Ganymede’s shadowSW IoGanymedeIo’s shadow30` bfmi _+agj^1 hj^2Path of Comet 88PAugust 1
5
10
15
20
25LIBRA
VIRGO
HYDRA
SpicaNE/ 4°+42 ASTRONOMY • AUGUST 2020
LIKE A GOOD CHILDHOOD
FRIEND who pops by for a
visit every few years, Comet
Howell changes but largely
stays the same, providing good
company between dusk and
midnight. You’ll need at least
a 4-inch scope out under dark
country skies to spot its soft
11th-magnitude glow. Try it
during the Perseids’ peak on
August 12 and again a week later
as it slides through Libra.
88P’s elliptical path brings it
just inside Mars’ orbit, looping
back out to Jupiter’s domain
roughly every 5.5 years. Gravity’s
adjustments brought it to us
and, millions of years in the
future, will likely eject it to
become another solar system’s
interstellar comet.
Don’t fret if at first you can’t see it. There’s a decent chance that haze and a longer path through the
atmosphere make 88P a challenge. Bump up the power past 100x, get comfortable, and look for a small,
elliptically shaped smudge floating southeast of the Virgo Cluster. Imagers will pick up the tint of classic
green. Next month the comet should be a magnitude brighter and more obvious.
While you’re in comet mode, take a peek at the fading Comet PanSTARRS (C/2017 T2) floating almost
30° away in Boötes.Io and Ganymede race across Jupiter
COMET SEARCH I Dependable returner
Comet 88P/Howell
side of the rings. A is the outer
ring, B is the brighter central
ring, and C is the dusky inner
ring. Rings A and B are sepa-
rated by the 2,980-mile-wide
Cassini Division, which is vis-
ible in a small telescope.
Saturn’s brightest moon,
Titan, glows at an easy 8th
magnitude. You’ll find Titan
due north of Saturn August 1
and 17, and due south on
August 9 and 25. A trio of 10th-
magnitude moons orbit closer
to the rings. Tethys, Dione, and
Rhea change their relative posi-
tions over the course of a few
hours. Enceladus is faint and
near the edge of the A Ring,
making it harder to see due to
the ring’s brilliance. You can
spot Iapetus less than 3' south-
west of Saturn on August 1,
when it shines about magnitude- The moon will brighten and
move west of Saturn, reaching
9' due west on August 17.
Slightly south of a line
between Saturn and Jupiter we
find Pluto. It’s really faint at
magnitude 14.6, but well within
reach of modern digital cam-
eras attached to a telescope.
Take a few images over several
nights to detect its motion.
Neptune is located in
northwestern Aquarius. The
ice giant rises after 10 P. M. local
time in early August and is up
by sunset on August 31. Grab a
pair of binoculars to pick up
the magnitude 7.8 planet. Find
4th-magnitude Phi (φ) Aquarii
and slew 3° east-northeast to
find the planet in early August.
By August 31 it’s only 2.5°
from the star. Note that 6th-
magnitude 96 Aquarii lies 1.5°
northeast of Phi. A sketch of
the stars each night will reveal
the planet by its motion. A tele-
scope will show its 2.4"-wide
bluish disk.Early August is the best
time this year to observe Ceres,
the closest dwarf planet to
Earth. On August 5, it lies only
4.5' southeast of the star 88
Aquarii. Ceres’ motion relative
to the star is noticeable within
an hour. It remains within 11'
of the star the day before and
after this close appulse.
Ceres reaches opposition on
August 28. That day, it’s located
roughly at the midpoint of a
line between 88 Aquarii and
Epsilon (ε) Piscis Austrini.
Ceres is an easy binocular tar-
get and brightens to magnitude
7.7 during the month.
Mars rises in the south
shortly before midnight local
time on August 1. It’s a dra-
matic object at magnitude –1.1
in Pisces the Fish. You’ll find it
roughly in line with a diagonal
drawn southeast across theSquare of Pegasus, from Scheat
through Algenib. Mars treks
briskly eastward and a waning
gibbous Moon passes 0.8°
south of the Red Planet on
August 9. By the last week ofSKY THIS MONTH — Continued from page 37
In one of several doubleheaders this month, Io and Ganymede trek across
Jupiter within hours of each other. Swing your scope upward at the right time,
and you can spot both moons and their shadows in a single glance.
EVENING SK Y
Jupiter (southeast)
Saturn (southeast)
Neptune (east)MIDNIGHT
Jupiter (south)
Saturn (south)
Mars (east)
Uranus (east)
Neptune (southeast)MORNING SK Y
Mercury (northeast)
Venus (east)
Mars (south)
Uranus (south)
Neptune (southwest)Magnitude 11 88P/Howell requires dark skies and at least a small scope to
spot — for now. The comet is still on its approach to the Sun and will
continue growing brighter throughout this month and into next.