Sky & Telescope - March 2025 - 46

MARCH 2025 OBSERVING
Sun, Moon & Planets by Gary Seronik
To find out what's
visible in the sky from
your location, go to
skyandtelescope.org.
A Big Month for the Moon and Venus
A set of conjunctions and a pair of eclipses are on the lunar docket in March.
SATURDAY, MARCH 1
Conjunctions between the Moon and
Venus are among the most arresting
naked-eye sights in astronomy. So,
what could be better than the chance to
see one? How about the chance to see
two in one month! What makes this
month's twofer so remarkable is that we
get one at dusk and the other at dawn
(see March 27, on the facing page).
As it happens, this evening's event
is the last one in the current Venus
apparition, which began back in June
2024. The 5%-illuminated waxing lunar
crescent sits less than 6½° lower left of
the Evening Star, which gleams magnificently
at magnitude -4.8. As twilight
fades, keep an eye out for earthshine on
the Moon's " unlit " side - pale light
reflected onto the lunar surface by the
95%-illuminated gibbous Earth.
If you have a reasonably unobstructed
western horizon, see if you
can add the bonus sight of Mercury,
positioned 10° lower right of the Moon.
The innermost planet currently shines
at magnitude -1.0, which should make
it reasonably easy to pick out even
through thin, horizon-hugging haze.
SATURDAY, MARCH 8
One week after Mercury was part of a
dusk triangle with the Moon and Venus,
the little planet reaches its greatest
elongation for this brief evening apparition.
Mercury is 18° east of the Sun - a
separation great enough that it lingers
above the western horizon for 1½ hours
after sundown. This is the first of three
dusk apparitions for Mercury in 2025.
As the horizon diagram below shows,
the current one is the most favorable.
This evening, Mercury shines at magnitude
-0.3 and has an altitude of 8°
about 45 minutes after sunset.
Even as Mercury reaches its highest
point, Venus is swiftly sinking
lower as it plunges toward inferior
conjunction with the Sun on March
23rd (UT). Venus passes Mercury on
the 12th, when the two planets are
about 5½° apart. By then, however,
Mercury has dimmed significantly to
magnitude +0.6, making it a much
tougher find. Binoculars are your friend
here - locate Venus first, then look for
Mercury to its left.
A little later on the evening of the
8th, a second lovely sight awaits. Nearly
overhead, the 75%-illuminated gibbous
Moon hangs less than 1½° above Mars.
The Red Planet is nearly two months
past opposition and has dimmed from
its peak brightness of magnitude -1.4
down to -0.1. Still, it's plenty prominent
even next to a bright Moon. What
makes this night's scene even more
impressive is that both objects lie near
Castor and Pollux in Gemini; the Moon
is about 5° from Pollux, the brighter
of the two stars. Taking in an even
wider view, you can create a wonder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.
2025 Evening Elongations of Mercury
45 minutes after sunset
Mercury
Mercury
5°
Mercury
WSW
Oct 29 (24°)
Sun
Mar 8 (18°)
Sun
W
WNW
Jul 4 (26°)
Sun
-5°
-10°
15°
10°
46
MARCH 2025 * SKY & TELESCOPE

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Sky & Telescope - March 2025

Table of Contents for the Digital Edition of Sky & Telescope - March 2025