What's Happening?
On December 18, 2025, Mercury is visible in the constellation Ophiuchus, accompanied by a slim, 2-percent-lit crescent Moon. The Moon is positioned to Mercury's lower right, creating a striking visual
for early morning skywatchers. The Moon will pass 6° south of Mercury at 7 A.M. EST and 0.4° south of the star Antares at 8 A.M. EST. Mercury, with a magnitude of -0.5, is 84 percent illuminated and located nearly 7° to the Moon's upper left. This celestial arrangement offers a unique opportunity for observation with binoculars or a telescope, especially to view the earthshine on the Moon.
Why It's Important?
This celestial event provides an excellent opportunity for amateur astronomers and sky enthusiasts to observe and photograph the alignment of Mercury and the Moon. The visibility of Mercury, often challenging due to its proximity to the Sun, is enhanced by its current position and illumination. Observing the earthshine on the Moon can also be a captivating experience, as it reveals the darkened regions of the lunar surface. Such events foster public interest in astronomy and can serve as educational moments for those learning about the night sky.
What's Next?
Skywatchers are encouraged to use binoculars or telescopes to enhance their viewing experience of Mercury and the Moon. As the Moon continues its cycle, it will soon reach its new phase, providing darker skies for observing other celestial phenomena, such as the upcoming Ursid meteor shower. These events highlight the dynamic nature of the night sky and the continuous opportunities for observation and study.
