Mercury farthest from sunrise January 12

At greatest elongation on January 12, 2024, Mercury lies to one side of the sun as seen from Earth. It’s at its greatest distance from the sun on our sky’s dome. Chart via John Jardine Goss/ EarthSky.

Mercury reaches greatest elongation – its greatest distance from the sun in the morning sky – on January 12, 2024. At that time, it’s 24 degrees from the sunrise.

The innermost planet Mercury orbits the sun every 88 days. And Earth is moving, too. So Mercury goes between us and the sun pretty often, about every 116 days. It did this last on December 22, 2023, reaching the point astronomers call inferior conjunction. Since then, Mercury has been speeding ahead of Earth in orbit. It re-emerged in our dawn sky, near the sunrise, below brilliant Venus, earlier this month. Now Mercury is reaching its greatest morning elongation – its greatest apparent distance from the rising sun – on January 12, 2024.

Due to the angle of the ecliptic – path of the sun, moon and planets – this time of the year, this January 2024 Mercury elongation is slightly better viewed from the Southern Hemisphere because the planet will reach a higher altitude on the sky dome. But northern skywatchers can see it, too! Many have reported seeing Mercury in recent days, on a line with blazing Venus and the soon-to-rise sun, before bright morning twilight interferes.

The innermost planet – named for the fleet-footed messenger god of the ancient Romans – will be visible into February.

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Mercury greatest elongation, January 2024

When to watch: Officially, Mercury became visible toward the end of December 2023 in the morning sky. But it was tough to see until the early days of the New Year. At greatest elongation – – January 12, 2024 – Mercury is farthest from the sunrise on our sky’s dome. And the planet will remain bright after that. Then, in early February, when it’ll be edging back toward the sunrise, it’ll brighten a little bit more, making Mercury easier to spot – although low – in the morning twilight.
Where to look: Look in the sunrise direction, as the sky is getting lighter. Mercury is on a line with Venus and the coming sunrise.
Greatest elongation is on January 12 at 15:00 UTC (9:00 a.m. CST). Mercury is shining at a 0.5 magnitude that morning. And it is 24 degrees from the sun.
Through a telescope on and around January 12, Mercury appears 64% illuminated, in a gibbous phase, and 6.8 arcseconds across.
Note: Once you spot it, notice that Mercury brightens quickly as January progresses, reaching a magnitude of around -0.5 (bright, but in bright morning twilight) before slipping away in the morning glare in February.

Finder charts, Northern Hemisphere

For viewers in the Northern Hemisphere, Mercury lies just above the horizon in the bright twilight shortly before sunrise in January. It’ll reach its greatest morning elongation – farthest from the sun in our morning sky – on January 12, 2024. At best, the planet reaches 24 degrees from the sun on that day. Then, it’ll brighten slightly after, later finally disappearing from the morning sky in February. Also, higher in the morning sky will be the brilliant light of the planet Venus. Chart via EarthSky.

For viewers in the Northern Hemisphere, Mercury lies below bright Venus and just above the horizon shortly before sunrise in early February. How long can you see it before it slips away? Chart via John Jardine Goss/ EarthSky.

Finder charts, Southern Hemisphere

For viewers in the Southern Hemisphere, Mercury will be low in the southeast below Venus shortly before sunrise. Chart via John Jardine Goss/ EarthSky.

For viewers in the Southern Hemisphere, Mercury lies low in the east below bright Venus shortly before sunrise. Each morning, it moves closer to the horizon. 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: Dates are listed based on UTC times

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)

Mercury charts from Guy Ottewell

Mercury’s greatest morning elongations in 2024 – from the Northern Hemisphere – as viewed through a powerful telescope. The planet images are at the 1st, 11th and 21st of each month. Here, dots show the actual positions of the planet for every day. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Mercury’s greatest morning elongations in 2024 from the Southern Hemisphere, as viewed through a powerful telescope. The planet images are at the 1st, 11th and 21st of each month. Here, dots show the actual positions of the planet for every day. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Heliocentric solar system, December 2023 and January 2024

Heliocentric view of solar system, December 2023. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Heliocentric view of solar system, January 2024. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

A comparison of elongations

Mercury’s greatest elongations are not equal. Indeed, some are “greater” than others. For example, the distance of Mercury from the sun on our sky’s dome varies from about 28 degrees (maximum) to 18 degrees (minimum).

Also, Mercury elongations are better or worse depending on the time of the year they occur and your location on Earth. So, for both hemispheres, spring evenings and autumn mornings are best.

The chart below – from a Northern Hemisphere perspective – might help you visualize these differences.

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 line). Likewise, maxima are reached at the parenthesized dates below (40 degrees north bold). Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Seasons make a difference

So, 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. Conversely, it makes a steep slant, nearly perpendicular, in the morning. So – in autumn from either hemisphere – morning elongations of Mercury are best. Then, Mercury appears higher above the horizon and farther from the glow of the sun. Evening elongations in autumn are, however, harder to see.

On the other hand, in the spring for either hemisphere, the situation reverses. The ecliptic and the horizon meet at a sharper angle on spring evenings and at 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.

Bottom line: Mercury reaches its greatest elongation – greatest distance from the sunrise – on January 12, 2024. Look east at dawn. It’ll brighten through early February before disappearing from the morning sky.

The post Mercury farthest from sunrise January 12 first appeared on EarthSky.