Mercury at greatest evening elongation, start watching now

Slanted green line of ecliptic through twilight, with dot near horizon labeled Mercury. — On December 4, Mercury reaches its farthest angular distance from the sun, known as greatest eastern elongation. On this date, it lies low in the southwest. Chart via John Jardine Goss/ EarthSky.

Mercury will reach its greatest elongation on December 4, 2023.

Mercury in November and December 2023

Where to look: Look west, in the sunset direction – shortly after sunset – for Mercury. The sun’s innermost planet may be challenging even for the more favored view from the Southern Hemisphere.
Greatest elongation: Mercury is farthest from the sun – at greatest elongation – at 14 UTC on December 4, 2023 (8 a.m. CDT on December 4). It’s 21 degrees from the sun.
Brightness: Mercury emerged in the evening sky the second week of November at -0.5 magnitude but it’s at a far southerly declination so it is difficult to observe for the Northern Hemisphere. At greatest elongation, Mercury shines at magnitude -0.3, making it brighter than most stars. But, after greatest elongation, the innermost planet will rapidly fade as it sweeps toward Earth. It’ll probably disappear by mid-month and will reach inferior conjunction – when it will pass between Earth and the sun – on December 22.
Through a telescope: Mercury will appear about 62% illuminated, at greatest elongation. It’ll measure 6.7 arcseconds across.
Constellation: Mercury will lie in front of the constellation Sagittarius the Archer at this elongation. But most of the stars in this constellation will be lost in the twilight.
Note: As the innermost planet, Mercury is tied to the sun in our sky. As a result, it never ventures very far above the horizon after sunset. So as soon as the sun disappears below your horizon, your clock starts ticking. Will you see the glowing point of light that is Mercury before it drops below the horizon, following the setting sun?

The 2024 lunar calendars are here! Best Christmas gifts in the universe! Check ’em out here.

Diagram: Earth and Mercury orbits with sun in middle and 2 red lines of sight from the Earth to Mercury and the sun. — At greatest elongation, Mercury is to one side of the sun and is at its greatest distance from the sun on our sky’s dome. Mercury reaches greatest eastern (evening) elongation from the sun on December 4, 2023. It is 21 degrees from the sun in the evening sky. Chart via John Jardine Goss/ EarthSky.

Finder charts for November Northern Hemisphere evenings

2 positions of thin crescent moon along the green ecliptic line and a dot for Mercury on the horizon. — The slender waxing crescent moon will hang low in the southwest shortly after sunset on the evening of November 15, 2023. Binoculars will help spot Mercury near the moon in the bright twilight. Chart via John Jardine Goss/ EarthSky.

Very low white dot for Mercury beside teapot-shaped group of stars along a green ecliptic line. — For viewers in the Northern Hemisphere, Mercury will lie just above the horizon in the bright twilight shortly after sunset in the second half of November 2023. The Teapot asterism of Sagittarius is nearby but it will be difficult to spot in the bright evening twilight. Chart via John Jardine Goss/ EarthSky.

Finder charts for November Southern Hemisphere evenings

White dot for Mercury, with arrow showing its path, and red dot for Antares along a green ecliptic line. — As viewed from the Southern Hemisphere, Mercury will appear low in the west shortly after sunset after November 10, 2023. Look for the bright red star Antares nearby. Chart via John Jardine Goss/ EarthSky.

Along green ecliptic line, thin crescent moon above, and red dot next to white dot for Antares and Mercury below. — As viewed from the Southern Hemisphere, Mercury will pass the star Antares on November 16, 2023. Chart via John Jardine Goss/ EarthSky.

Low white dot for Mercury below teapot-shaped group of stars along a green ecliptic line. — During the second half of November 2023, Mercury will lie low in the west below the Teapot asterism of Sagittarius shortly after sunset. Chart via John Jardine Goss/ EarthSky.

For precise sun and Mercury rising times at your location:

Old Farmer’s Almanac (U.S. and Canada)
timeanddate.com (worldwide)
Stellarium (online planetarium program)

Mercury events in 2023 and 2024

Note: Times are in UTC

Jan 7, 2023: Inferior conjunction (races between Earth and sun)
Jan 30, 2023: Greatest elongation (morning)
Mar 17, 2023: Superior conjunction (passes behind sun from Earth)
Apr 11, 2023: Greatest elongation (evening)
May 1, 2023: Inferior conjunction (races between Earth and sun)
May 29, 2023: Greatest elongation (morning)
Jul 1, 2023: Superior conjunction (passes behind sun from Earth)
Aug 10, 2023: Greatest elongation (evening)
Sep 6, 2023: Inferior conjunction (races between Earth and sun)
Sep 22, 2023: Greatest elongation (morning)
Oct 20, 2023: Superior conjunction (passes behind sun from Earth)
Dec 4, 2023: Greatest elongation (evening)
Dec 22, 2023: Inferior conjunction (races between Earth and sun)

Jan 12, 2024: Greatest elongation (morning)
Feb 28, 2024: Superior conjunction (passes behind sun from Earth)
Mar 24, 2024: Greatest elongation (evening)
Apr 11, 2024: Inferior conjunction (races between Earth and sun)
May 9, 2024: Greatest elongation (morning)
Jun 14, 2024: Superior conjunction (passes behind sun from Earth)
Jul 22, 2024: Greatest elongation (evening)
Aug 19, 2024: Inferior conjunction (races between Earth and sun)
Sep 5, 2024: Greatest elongation (morning)
Sep 30, 2024: Superior conjunction (passes behind sun from Earth)
Nov 16, 2024: Greatest elongation (evening)
Dec 5, 2024: Inferior conjunction (races between Earth and sun)
Dec 25, 2024: Greatest elongation (morning)

Heliocentric view of Mercury December 2023

Circle with sun at center, planets around, and zodiac names on outer edge. — View larger. | Heliocentric view of solar system, December 2023. Chart via Guy Ottewell Used with permission.

A comparison of elongations

The farthest from the sun that Mercury can ever appear on the sky’s dome is about 28 degrees. And the least distance is around 18 degrees.

Also, elongations are better or worse depending on the time of year they occur. So in 2023, the Southern Hemisphere had the best evening elongation of Mercury in August 2023. And the Northern Hemisphere had the best evening apparition in April.

In the autumn for either hemisphere, the ecliptic – or path of the sun, moon and planets – makes a narrow angle to the horizon in the evening. But it makes a steep slant, nearly perpendicular, in the morning. So, in autumn from either hemisphere, morning elongations of Mercury are best. That’s when Mercury appears higher above the horizon and farther from the glow of the sun. However, evening elongations in autumn are harder to see.

In the spring for either hemisphere, the situation reverses. The ecliptic and horizon meet at a sharper angle on spring evenings and a narrower angle on spring mornings. So, in springtime for either hemisphere, evening elongations of Mercury are best. Meanwhile, morning elongations in springtime are harder to see.

Chart with row of alternating light blue and gray arcs, each with a date and height in degrees. — View larger. | Mercury elongations compared. Here, gray areas represent evening apparitions (eastward elongation). Blue areas represent morning apparitions (westward elongation). The top figures are the maximum elongations, reached at the top dates shown beneath. Curves show the altitude of the planet above the horizon at sunrise or sunset, for latitude 40 degrees north (thick line) and 35 degrees south (thin). Maxima are reached at the parenthesized dates below (40 degrees north in bold type). Chart via Guy Ottewell’s 2023 Astronomical Calendar. Used with permission.

More Mercury elongation comparisons for 2023

Annotated sky chart with arced rows of dots for positions of planet, and dashed line for celestial equator. — View larger. | Mercury’s greatest evening elongations in 2023 from the Northern Hemisphere as viewed through a powerful telescope. The planet images are at the 1st, 11th, and 21st of each month. Dots show the actual positions of the planet for every day. Chart via Guy Ottewell. Used with permission.

Sky chart with constellations, arc-shaped dotted planet paths, and objects labeled. — View larger. | Mercury’s greatest evening elongations in 2023 from the Southern Hemisphere as viewed through a powerful telescope. The planet images are at the 1st, 11th, and 21st of each month. Dots show the actual positions of the planet for every day. Chart via Guy Ottewell. Used with permission.

Mercury photos from our community

Sunset with tall, narrow, bare trees to left and label of Mercury on small dot in blue twilight sky. — View at EarthSky Community Photos. | Joel Weatherly in Edmonton, Alberta, Canada, took this image on April 23, 2022. Joel wrote: “Lonely little Mercury is making an appearance in our evening skies. Despite being elusive, it was easy to see without optical aid once sighted.” Thank you, Joel!

Silhouette of lifeguard tower in the foreground, crescent moon and Mercury in an orange and blue twilight sky. — View at EarthSky Community Photos. | Chix RC captured this image on January 3, 2022, from Hermosa Beach, California. See Mercury to the upper right of the crescent? Chix wrote: “A faint young moon at 1% illumination and Mercury.” Thank you, Chix!

Crescent moon, 2 labeled dots (Mercury and Venus) in blue and orange sky over a lighted suspension bridge. — View at EarthSky Community Photos. | Alexander Krivenyshev of the website WorldTimeZone.com captured this photo of the moon together with Mercury and Venus on May 13, 2021, from Newport, Rhode Island. Thank you, Alexander!

Bottom line: Mercury is visible in the evening sky. Look in the west as the sky is darkening. The planet will reach its greatest elongation overnight on December 4, 2023.

Submit your photos to EarthSky here.

Read about greatest elongations, superior and inferior conjunctions: Definitions for stargazers

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