Image title: Moon-Mercury-Pleiades ConjunctionAuthor: Giulio ColomboCountry: Italy This photograph shows the young lunar crescent, some of the nine brightest stars of the Pleiades (with one behind a cloud) on the right, and the planet Mercury, looking slightly red, in the middle of the image. This picture is rather suggestive of the idea that the Pleiades might possibly consist of seven stars. However, the viewer is misled by the clouds; five of the stars form a tiny chariot, one is next to the handle, and three are at the other end of the quadrilateral. Eight stars would be clearly visible if there were no clouds. This configuration of the young Moon next to the Pleiades is visible only in the northern hemisphere spring. Thus it was used by the ancient Babylonians to determine the second month of their year and to judge whether or not an intercalary month was necessary. At least as early as the second millennium before the common era, the Babylonians used several asterisms for each month, with another one of them reappearing every five days after invisibility during daylight. To determine the necessity of intercalation in order to synchronise the solar and the lunar year, the Babylonians used several asterisms, not only the Pleiades. For instance, they also made use of the bright stars Arcturus and Sirius, and they observed a configuration with the Moon as well as heliacal phenomena. The modern Jewish and modern Islamic traditions still make use of some of the Babylonian astronomical rules. However, given that the constellations have shifted as a result of precession, and the fact that nowadays we also have computational means to calculate our calendars, this configuration of the small crescent Moon and the Pleiades is less useful, though it remains exceptionally beautiful. Thus the ancient Babylonian and middle Babylonian tradition survives only rudimentarily. Furthermore, it is unlikely that it is depicted in the Nebra Disc from Bronze Age Europe, as has long been claimed. This image was taken on Elba Island, Italy, in May 2022. Also see image in Zenodo: https://doi.org/10.5281/zenodo.7425575

Featured Image. Credit CC BY-SA 3.0, via Wikimedia Commons

Suhail Ahmed

Have You Seen This? The Moon ‘Kisses’ Mercury and Mars in June’s Cosmic Show

Astronomy, Celestial events, Mars, Mercury, Moon conjunction

Suhail Ahmed

The night sky of June is expected to show a pair of amazing conjunctions one with the elusive Mercury and the other with a remarkably near encounter between the Moon and Mars. These events serve as a reminder of the clockwork accuracy of our solar system and an opportunity to see planetary motions that even ancient astronomers would have delighted at, not only beautiful alignments. Often lost in the Sun’s glare, Mercury will momentarily show up as a twilight gem; Mars and the Moon will show up nearer than the width of a full Moon apart close enough in the celestial sphere to “kiss”. Here is all you need to seize these ephemeral events.

Why Mercury’s Appearance Is So Special

Image by Ed Dunens, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

The smallest and fastest planet in the solar system, mercury is also rather difficult to find. Its close orbit around the Sun means it never strays far from the blinding light of our star, hence it is only seen in fleeting windows at dawn or evening. For skywatchers, Mercury will, however, climb just high enough above the western horizon after sunset to be seen with the unaided eye this month.

A delicate crescent Moon will pass Mercury on June 26 and 27, creating an arresting lineup with the twin stars of Gemini, Pollux, and Castor adding to the show. Mercury’s consistent, yellowish glow will be wonderfully contrasted with the thin form of the Moon, which just reflects sliver of sunlight. But timing is crucial; Mercury sets quickly; hence, binoculars and a clear western view will be useful.

Mars and the Moon: A Cosmic Close-Up

Image by Sean Rozekrans from Amsterdam, Netherlands, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

While Mercury’s cameo is fleeting, the Moon-Mars conjunction on June 29 promises an even more dramatic sight. The two will be separated by a mere 0.2 degrees about one-third the width of the full Moon making them appear to nearly touch in the sky. This proximity is unusual; most conjunctions involve wider gaps.

Mars, the “Red Planet,” will shine with its characteristic rusty hue just below the Moon’s crescent, creating a photogenic duo in the constellation Leo. The pairing will be visible to the unaided eye, but a telescope will reveal an even more stunning detail: both objects will fit into the same field of view, offering a rare chance to see Earth’s satellite alongside another world in sharp detail.

The Science Behind Conjunctions

Image by Tfr000 (talk) 16:54, 15 March 2012 (UTC), CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Why then do these incidents occur? The flat plane along which planets orbit the Sun, the ecliptic, holds the solution. Periodically, the Moon crosses close to planets from our vantage point since its path around Earth is just five degrees relative to this plane.

Though they sometimes produce tight conjunctions, these crossings have an amazing effect. The Moon’s apparent speed across its own diameter each hour causes its position to vary noticeably night to night, producing dynamic pairings such as the highlights for this month.

How to Watch (and Photograph) the Events

A couple stargazes under a starry sky in Elkton, VA, capturing the beautiful Milky Way.
Image by Yuting Gao via Pexels
  • For Mercury (June 26–27): Look west 30–45 minutes after sunset. A clear horizon and binoculars will help spot the planet before it disappears into twilight.
  • For Mars (June 29): Face west after dark. The duo will be high enough to see even from light-polluted areas, but a dark sky will enhance the view.
  • Photography tip: Use a tripod and a medium telephoto lens (100–300mm) to capture the Moon and Mars together. Mercury may require a wider shot to include the Gemini stars.

A Historical Perspective: Conjunctions in Human Culture

Image by ‘Matthew G. Bisanz, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

Conjunctions have long fascinated civilizations. The ancient Babylonians tracked them for omens, while Mayan astronomers used them to refine their calendars. Even today, close pairings like this month’s Mars-Moon meet-up spark wonder and sometimes confusion. (No, Mars won’t collide with the Moon, despite how close they appear!).

What’s Next? More Skywatching Delights in 2025

Image by Fernando de Gorocica, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons

If you miss these events, don’t worry: planetary conjunctions happen regularly. Later this year, Saturn will cozy up to Jupiter in a rare “great conjunction,” and a total lunar eclipse will turn the Moon blood red on March 14, 2025 10. But for now, mark your calendar for June’s cosmic kisses, they’re a reminder that the universe loves a good show.

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