Two rare twilight pairings will grace the June 2025 sky as the moon first passes close to elusive Mercury and then gets stunningly close to Mars.
Mercury is typically difficult to see and the conjunction between Mars and the moon will be particularly close, so both will be special sights for skywatchers.
The moon and Mercury meet-up comes as the “Swift Planet,” which orbits the sun every 88 days, emerges from our star’s glare into the post-sunset sky between June 21 and 30. According to NASA, Mercury will be visible just above the western horizon for 30 to 45 minutes after sunset.
On Thursday (June 26), a very slim crescent moon will appear between Mercury and the two bright stars in the constellation Gemini — Pollux and Castor — causing a brief line of lights in the post-sunset night sky. On Friday (June 27), the crescent moon will be higher in the sky, just above Mercury.
Precisely how low Mercury is, and how long it’s observable during this period, depends on your location, so check Timeanddate.com or Stellarium.
That also applies to seeing what is arguably the skywatching highlight of the month on Sunday (June 29), when amateur astronomers will get a stunning view of a 24%-illuminated crescent moon directly beneath Mars in the constellation Leo, with just 0.2 degrees (12 arcminutes) separating them. The two worlds will appear so close that a fingertip held at arm’s length will cover them.
The sight will be high in the western sky and easily visible without any equipment, but the two celestial bodies will be so close that they’ll fit into the same field of view of a telescope. Although it’s rare to see the moon and Mercury together in the night sky, and the closeness of the moon and Mars is also unusual, conjunctions between our natural satellite and planets are not uncommon. Planets orbit the sun on more or less the same plane, called the ecliptic. It’s the same path the sun takes through the daytime sky as seen from Earth. The moon’s orbit of Earth isn’t quite the same, but its rather wobbly path differs from the ecliptic by only five degrees. Twice a month, the moon crosses the ecliptic (hence the name, because that sometimes causes solar and lunar eclipses), so it can come particularly close to a planet as seen from our terrestrial viewpoint.
The next significant close planetary conjunction will be the meeting of Venus and Jupiter in the pre-dawn hours of Aug. 12, when the two brightest planets will form a dazzlingly close pair.
Originally published on Live Science.
