Sky & Telescope - October 2022 - 46

OCTOBER 2022 OBSERVING
Sun, Moon & Planets by Gary Seronik
To find out what's
visible in the sky from
your location, go to
skyandtelescope.org.
A Month of Lunar Rendezvous
The Moon visits four planets and a bright star in October.
THURSDAY, OCTOBER 6
If you go outside and face south this
evening at around 11 p.m., you'll be
greeted by the alluring sight of a waxing
gibbous Moon bracketed by Saturn and
Jupiter. The two planets are nearly 44°
apart, and the Moon is roughly in the
middle - a couple of degrees closer to
Saturn than to Jupiter. But the apparent
distances between these worlds presents
only a two-dimensional picture. To
fully appreciate the scene before you,
consider the extreme depth-of-field (to
borrow a photographic term) involved.
Sunlight reflecting off the lunar surface
takes just a touch longer than 1 second
(1.23 seconds, to be precise) to reach
your eyes this evening. Even though
Jupiter has just had its closest opposition
in nearly six decades, it's obviously
much more distant than the Moon.
These scenes are drawn for near the
middle of North America (latitude 40° north,
longitude 90° west).
Dusk, Oct 7 - 9
1 hour after sunset
10°
PISCES
Jupiter
Moon
Oct 7
Moon
Oct 8
Moon
Oct 9
Moon
Oct 15
Moon
Oct 14
GEMINI
TAURUS
Mars
This evening the giant planet is far
enough away that light bouncing off its
cloudtop " surface " takes 1,982 seconds
to arrive here. In other words, Jupiter
is more than 1,600 times farther away
than good ol' Luna. And what about
remote Saturn? Here we're talking
about 4,616 seconds - more than twice
as long as for Jupiter. So, this evening's
scene includes light-travel times of
roughly 1 second, half an hour, and
11
/3 hours. That's more impressive to
contemplate than 44°, isn't it?
SATURDAY, OCTOBER 8
Moving on . . . and that's exactly what
the Moon does. This evening it leaves
Saturn far behind and sits left of
Jupiter. Because it has already passed
Jupiter, the Moon is drifting farther and
Oct 13 - 15
11 pm
farther away from the planet. So, the
earlier you look, the closer the pair will
be. For observers on the East Coast, just
a bit more than 3° separates the Moon
and Jupiter as twilight dims. However,
by the time they rise on the West Coast,
that gap has grown to more than 4½°.
Even if this isn't the closest Moonplanet
pairing of the month (see October
14th), it's arguably the most eyecatching.
That's because Jupiter gleams
at its peak brightness of magnitude -2.9.
This brilliance, plus its proximity to the
nearly full Moon, are both indicators
that the planet is not far removed from
its September 26th opposition.
FRIDAY, OCTOBER 14
Skipping eastward along the ecliptic, the
Moon joins Mars for its closest October
Oct 20-22
5 am
Moon
Oct 20
η
Capella
Regulus
AURIGA
Moon
Oct 13
LEO
Moon
Oct 21
Denebola
Moon
Oct 22
Looking East-Southeast
Looking East-Northeast
46
OCTOBER 2022 * SKY & TELESCOPE
Looking East
http://www.skyandtelescope.org
Sky & Telescope - October 2022

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