Mercury Greatest Morning Elongation October 8 - EarthSky

Mercury farthest from the sunrise on April 3

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 at 11 UTC on March 7, 2026, reaching the point astronomers call inferior conjunction. And since then, Mercury has been speeding ahead of Earth in orbit. It re-emerged into our eastern morning sky in mid-March. Look for it in the sunrise direction. Mercury will reach its greatest morning elongation – its greatest apparent distance from the rising sun – on April 3, 2026. This morning apparition favors the Southern Hemisphere.

Mercury greatest elongation, April 2026

When to watch: Officially, Mercury emerged in mid-March in the morning sky. Look for it shortly before sunrise. At greatest elongation – April 3, 2026 – Mercury is farthest from the sunrise on our sky’s dome. And after that, when it’ll be edging back toward the sunrise, it’ll brighten a little bit more, making Mercury easier to spot in the morning twilight. It’ll be low in the sky! This is the best morning apparition of Mercury for the Southern Hemisphere in 2026. Where to look: Look in the sunrise direction as the sky is getting lighter. Greatest elongation – marking Mercury’s farthest point from the sunrise glare – is on April 3, 2026 at 23 UTC (6:00 p.m. CDT). Mercury will shine at magnitude +0.4 that morning. At that time, Mercury will be 28 degrees from the sun on our sky’s dome. Through a telescope on and around April 3, Mercury appears 50% illuminated, in a quarter phase, and 7.64 arcseconds across. Note: After April 3, Mercury brightens a bit to magnitude -0.3 (bright, but competing with the morning twilight) until late April or early May. Around that time, it’ll slip away in the morning twilight. Mercury, Saturn and Mars conjunction: About 30 minutes before sunrise on April 20, look for Mercury, Saturn and Mars to lie near each other in the morning twilight. Binoculars might help spot the trio of planets.

By the way, this Mercury elongation – due to the high angle of the ecliptic to the horizon – favors the Southern Hemisphere.

After greatest elongation on April 3, the innermost planet – named for the fleet-footed messenger god of the ancient Romans – will be visible for a few more weeks, especially from the Southern Hemisphere.

For precise sun and Mercury rising times at your location:

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

Mercury events in 2026

Note: Times are in UTC

Jan 21, 2026: Superior conjunction (passes behind sun from Earth) Feb 19, 2026: Greatest elongation (evening) Mar 7, 2026: Inferior conjunction (races between Earth and sun) Apr 3, 2026: Greatest elongation (morning) May 14, 2026: Superior conjunction (passes behind sun from Earth) Jun 15, 2026: Greatest elongation (evening) Jul 13, 2026: Inferior conjunction (races between Earth and sun) Aug 2, 2026: Greatest elongation (morning) Aug 27, 2026: Superior conjunction (passes behind sun from Earth) Oct 12, 2026: Greatest elongation (evening) Nov 4, 2026: Inferior conjunction (races between Earth and sun) Nov 21, 2026: Greatest elongation (morning)

Mercury charts from Guy Ottewell

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’s 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.

As an illustration, the chart below – from a Northern Hemisphere perspective – might help you visualize these differences.

Heliocentric solar system, April 2026

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. Conversely, evening elongations in autumn are harder to see.

On the other hand, in the spring for either hemisphere, the situation reverses. Then, 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 will reach its greatest elongation – greatest distance from the sunrise – on April 3, 2026. Look east at dawn. It’ll disappear from the morning sky in late April.

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