Mercury is up before sunrise and visible until mid-June

On May 1, 2023, Mercury passed very close to the sun. In fact, if its inferior conjunction was about a week later, it would transit the sun. Even though a transit didn’t happen, Mercury was headed for its greatest morning elongation on May 29, 2023. This elongation is best viewed from the Southern Hemisphere where it rises about two hours before sunrise and will be visible until around mid-June.

At greatest elongation in May 2023

When to watch: Mercury became visible in mid-May 2023. It’s especially easy to find if you’re in the Southern Hemisphere, where the ecliptic (the green line on our charts) makes a steep angle with the eastern predawn horizon. Greatest elongation – when Mercury will be farthest from the sunrise on our sky’s dome – will be May 29. But the planet will continue getting brighter after that. So, in early June, although it’ll be edging back toward the sunrise, Mercury will be easier to spot in the morning twilight.
Where to look: Look in the sunrise direction, as the sky is getting lighter.
Greatest elongation is on May 29 at 6 UTC (1 a.m. CDT). Mercury will be shining at +0.6 magnitude that morning. And it’ll be 24.9 degrees from the sun.
Through a telescope on and around May 29, Mercury will appear 38% illuminated, in a crescent phase, and 8.2 arcseconds across. By the way, in mid-June it’ll be almost 75% illuminated by the time it slips out of view for Southern Hemisphere observers.
Note: Once you spot it, notice that Mercury brightens quickly in June, reaching around -1.0 magnitude before slipping away in the morning glare in mid-June.

Mercury in Southern Hemisphere in May 2023

June 15 and 16 mornings: Moon near Mercury

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

January 7, 2023: Inferior conjunction (races between Earth and sun)
January 30, 2023: Greatest elongation (morning)
March 17, 2023: Superior conjunction (passes behind sun from Earth)
April 11, 2023: Greatest elongation (evening)
May 1, 2023: Inferior conjunction (races between Earth and sun)
May 29, 2023: Greatest elongation (morning)
July 1, 2023: Superior conjunction (passes behind sun from Earth)
August 10, 2023: Greatest elongation (evening)
September 6, 2023: Inferior conjunction (races between Earth and sun)
September 22, 2023: Greatest elongation (morning)
October 20, 2023: Superior conjunction (passes behind sun from Earth)
December 4, 2023: Greatest elongation (evening)
December 22, 2023: Inferior conjunction (races between Earth and sun)

Heliocentric view of Mercury May 2023

A comparison of elongations

Not all of Mercury’s greatest elongations, however, are created equal. In fact, some are greater than others. That’s because the farthest from the sun that Mercury can ever appear on the sky’s dome is about 28 degrees. On the other hand, the least distance is around 18 degrees.

Also, elongations are better or worse depending on the time of year they occur and your location on Earth.

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. On the other hand, however, evening elongations in autumn are harder to see.

On the other hand, 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.

Bottom line: Watch for Mercury in the east before sunup around mid-May 2023. Mercury reaches greatest elongation – its greatest distance from the sunrise – on May 29 and then brightens through mid-June. It’s best viewed from the Southern Hemisphere.