Sky & Telescope - August 2020 - 46

AUGUST 2020 OBSERVING
Sun, Moon & Planets by Fred Schaaf
To find out what's
visible in the sky from
your location, go to
skyandtelescope.org.

A Parade of Bright Planets
Jupiter, Saturn, Mars, and Venus put on a fine summer show.

A

few hours after sunset this month,
Jupiter and Saturn are at their
highest in the south at nearly the same
time Mars rises. On the other hand,
brilliant Venus rises several hours
before dawn, which by late August is
when Jupiter and Saturn set.
These planets all look great in telescopes this month. Jupiter and Saturn
were both at opposition around midJuly, and Venus is at greatest elongation
in mid-August. Mars is still two months
away from its impressive opposition
but is already big enough for some truly
extraordinary views of its surface.

Jupiter dims a bit from magnitude
-2.7 to -2.6, and Saturn's brightness
decreases from magnitude +0.1 to +0.3.
Jupiter's apparent diameter shrinks
from 47″ to 44″, and Saturn diminishes
ever so slightly, from 18.4″ to 18.0″.
Its rings remain well-displayed at 42″
across and tilted more than 22° from
horizontal. Calm summer nights are
usually good for obtaining crisp, steady
images in a scope, but because Jupiter
and Saturn are quite far south from
mid-northern latitudes they're viewed
through air that is often turbulent.
The dwarf planet Ceres, the largest
body in the asteroid belt, is at opposition on the 28th. It shines at magnitude
7.7 from southern Aquarius (see page 50
for a ﬁnder chart).

DUSK AND EVENING
Jupiter and Saturn shine in the southsoutheast after dusk. They start the
month almost 8° apart and continue
slowly pulling away from each other as
they both retrograde (move westward)
in eastern Sagittarius. During August,
X These scenes are
drawn for near the
middle of North America (latitude 40° north,
longitude 90° west);
European observers
should move each
Moon symbol a quarter of the way toward
the one for the previous date. In the Far
East, move the Moon
halfway. The blue 10°
scale bar is about the
width of your fist at
arm's length. For clarity, the Moon is shown
three times its actual
apparent size.

LATE EVENING TO DAWN
Mars rises 3 hours after sunset at the
beginning of August and 2 hours after

PRE-DAWN TO DAWN
Venus rises at virtually the same time
all month for observers at mid-northern
latitudes, who will see the planet clear
the horizon at around 2:45 a.m., local
daylight-saving time. Because the Sun

Dusk, July 31 - Aug 3

Dawn, Aug 8 -10

1 hour after sunset

1 hour before sunrise
Moon
July 31
Jupiter

10°

Saturn

CA PRICORNUS

Moon
Aug 1

S A G I T TA R I U S

Moon
Aug 10

Mars
Moon
Aug 9
Moon
Aug 8

Moon
Aug 2
Moon
Aug 3

Looking Southeast

46

sunset by the end of the month. The
Red Planet ﬂames up from magnitude
-1.1 all the way to -1.8 during that
time as it continues to move with direct
(eastward) motion through Aquarius.
Mars reaches perihelion (nearest to
the Sun in space) on the 3rd - a little
more than two months before what will
be one of the planet's closest oppositions. During August, Mars's apparent
diameter grows from 14.6″ to 18.7″.
The steadiest views in a telescope usually come when the planet is near the
meridian, which happens half an hour
before sunrise on the 1st and 2½ hours
before sunrise on the 31st.

AUGUST 2 02 0 * SK Y & TELESCOPE

Looking South, high in the sky
http://www.skyandtelescope.org
Sky & Telescope - August 2020

Table of Contents for the Digital Edition of Sky & Telescope - August 2020
