Sky & Telescope - March 2021 - 46

MARCH 2021 OBSERVING
Sun, Moon & Planets by Gary Seronik
To find out what's
visible in the sky from
your location, go to
skyandtelescope.org.

Red Planet Rendezvous
Mars has a close dusk encounter with the Pleiades, while Jupiter and Mercury meet at dawn.
THURSDAY, MARCH 4

FRIDAY, MARCH 5

Mars has been drifting closer and
closer to the Pleiades, and this evening
it's at its very closest - just a shade
more than 2½° from the cluster's center. Shining at magnitude 1.0, the Red
Planet has been within a 5° binocular
ﬁeld of the Pleiades since February 25th
and remains so until March 11th. And
though the sight can be appreciated
with your eyes alone, binoculars or a
small, wide-ﬁeld telescope adds many
more Pleiads to the mix and enhances
the color contrast between the icy-blue
cluster stars and the ruddy planet.
What's particularly notable about
the March 4th encounter is that Mars
hasn't been this close to the Pleiades
since 2006, and you'll have to wait until
2038 to see it pass this near again. Look
for both objects high in the southwest
at nightfall. Mars and the cluster set
around midnight, local standard time.

Early risers have an added incentive to
get up before dawn today as fast-moving
Mercury pulls up alongside lumbering
Jupiter low in the east-southeast. The
two planets will be nearest each other
this morning at 5:55 UT, when they're
separated by just a little more than 19′.
By the time the pair rises for observers
on the East Coast of North America,
the gap between the planets will have
widened a hair, to about 21′.
Mercury shines at magnitude +0.1
while Jupiter gleams at magnitude -2.0,
ensuring a wonderfully eye-catching
sight. And that's without taking into
account Saturn, loitering 8½° to the
upper right and shining at magnitude
+0.7. Aim binoculars or a telescope
(with modest magniﬁcation) at the
tight twosome and you'll get to include
a couple of Jupiter's moons in the view
as well. If the weather doesn't cooperate

on the 5th, bear in mind that Mercury
is less than 1° from Jupiter on the
mornings of the 4th and 6th as well.

SATURDAY, MARCH 6
Today Mercury has its greatest elongation from the Sun, with the planet
positioned 27.3° west of the solar disk.
This is the biggest separation between
the two objects for all of 2021, and
yet the result is a decidedly mediocre
showing for Mercury. It rises around
one hour ahead of the Sun and was
actually higher in the morning sky at
the end of February. Why is that? It's
because the ecliptic is canted at a rather
shallow angle with the dawn horizon
during spring for observers at midnorthern latitudes. Your best opportunity to catch Mercury in the morning
sky occurs in October, even though the
planet will then be nearly 10° closer to
the Sun than on March 6th. You can

TX 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.

Dusk, March 4
1 hour after sunset

Dawn, March 5

Dawn, March 9 -10

30 minutes before sunrise

CAPRICORNUS

CAPRICORNUS
TA U R U S

10°
Saturn
Pleiades

Aldebaran

Jupiter

MARCH 2 021 * SK Y & TELESCOPE

Jupiter

Mercury

Mars

Looking Southwest,
almost overhead

Saturn

Mercury

Looking East-Southeast

Moon
Mar 10

Looking Southeast

Moon
Mar 9

http://www.skyandtelescope.org

Sky & Telescope - March 2021

Table of Contents for the Digital Edition of Sky & Telescope - March 2021