Sky & Telescope - August 2019 - 47

brightness and size in August. The
golden world's magnitude diminishes
from +0.2 to +0.3 and its equatorial diameter from 18.3″ to 17.6″ this
month. The rings remain tilted to 24.7°,
just a few degrees from their maximum angle. As with Jupiter this year,
Saturn's southerly position calls for
observing it in the telescope when it's
at its highest, crossing the meridian.
It transits around 11:30 p.m. daylightsaving time at the start of August and
before 9:30 p.m. at month's end. Saturn
shines between the little, dim Teaspoon
of Sagittarius and the bright handle of
the Teapot of Sagittarius. It continues to
retrograde and closes the gap from 5°
to 4° between itself and magnitude-2.1
Nunki, or Sigma (σ) Sagittarii. Saturn
sinks below the horizon around 4 a.m.
in early August and around 2 a.m. at
the end of the month.

December
solstice

Uranus

Venus

Neptune

Earth

Saturn

June
solstice

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

much of the month is at its highest
after the start of morning twilight. See
https://is.gd/urnep for a ﬁnder chart
to help you locate Neptune in Aquarius
and Uranus in Aries.

DAWN
Mercury has its best morning apparitions for observers at mid-northern
latitudes within a month or two of the
autumn equinox. On August 3rd it rises
more than an hour before the Sun but
has brightened only to magnitude 1.4 so

Dawn, Aug 23 - 25

30 minutes before sunrise

1 hour before sunrise

GEMINI

Moon
Aug 24
Moon
Aug 25

Pollux

MOON PASSAGES
The Moon is waxing gibbous, close
to Beta (β) Scorpii at nightfall on
August 8th. The next evening, the Moon
beams some 2° upper left of Jupiter
at nightfall, with Antares not too far,
around 6°, lower right of the planet. On
the 11th, the still-swelling Moon is not
far to the right of Saturn. The Moon is
a waning crescent around 2° above or
upper left of Aldebaran on the morning
of the 24th, and less than ½° from Zeta
(ζ) Tau on the morning of the 25th. Find
an even thinner lunar crescent lower
right of Pollux at dawn on the 28th.

Aldebaran

TA U R U S

Mercury
Procyon
Betelgeuse

is just marginally visible (use binoculars). On August 9th, however, Mercury
reaches a greatest western elongation
of 19° from the Sun, shines at zero
magnitude, and rises about 90 minutes before the Sun for viewers around
latitude 40°N. The little world is only
about 38% illuminated that morning.
It stands more than 10° above the eastnortheast horizon by 30 minutes before
sunrise that day. Mercury continues to
brighten throughout August but drops
deep enough into the Sun's glow to be
lost from view by about August 26th
on its way to superior conjunction on
September 3rd.

Pleiades

Moon
Aug 23

ORION
Rigel

Looking East-Northeast

Sept.
equinox

Sun

Jupiter

Dawn, Aug 10

Castor

Mercury

March
equinox

NIGHT TO DAWN
Neptune reaches opposition on
September 10th but in August transits the meridian well after midnight
daylight-saving time. Uranus, two
magnitudes brighter than its fellow
ice giant Neptune, doesn't rise until
after evening twilight begins and for

Mars

Looking Southeast, high in the sky

¢ FRED SCHAAF is the author of The
Starry Room: Naked Eye Astronomy in
the Intimate Universe, a collection of essays published by Dover Publications.
sk yandtele scope.com * AUGU S T 2 019

47
https://www.is.gd/urnep http://www.skyandtelescope.com
Sky & Telescope - August 2019

Table of Contents for the Digital Edition of Sky & Telescope - August 2019
