Geminid Meteor Shower, Mercury’s Western Elongation, and the Moon Near the Pleiades Light Up the December Night Sky!
The winter night sky is filled with bright stars, making December’s celestial scenery exceptionally splendid. This month features Mercury’s western elongation, the final major meteor shower of the year—the Geminids—and a close encounter between the Moon and the Pleiades to accompany the New Year. Skywatchers are in for a treat!December 8 (Mon): Mercury at Western ElongationThis will be the last good opportunity of the year to observe Mercury. Shining at magnitude –0.5, Mercury can be spotted between 5:30 a.m. and dawn by looking toward the low east-southeast horizon. It won’t be difficult to find this planet, which is usually challenging to observe.December 14 (Sun): Geminid Meteor Shower PeakThe Geminids, the most spectacular meteor shower of the year, will reach their peak with an estimated Zenithal Hourly Rate (ZHR) of about 150—meaning observers may actually see around 100 meteors per hour. The Moon will be a waning crescent and won’t rise until around 2:30 a.m., so moonlight will have little impact on viewing. The Geminids are known for their slow to moderately fast meteors and occasional bright fireballs—don’t miss this magnificent meteor display!Winter Solstice — December 21 (Sun)On this day, the Sun shines directly on the Tropic of Capricorn, and the Northern Hemisphere experiences its shortest day and longest night of the year, with only 10 hours and 34 minutes of daylight. Although the solstice is not the day of the latest sunrise or earliest sunset, it is when both sunrise and sunset positions are at their southernmost points of the year. It’s a great opportunity to observe this interesting phenomenon.December 31 (Wed): The Moon and the PleiadesAfter sunset, the Moon and the Pleiades will appear together in the western sky. As the night progresses, the Moon will move close to and glide past the jewel-like Pleiades star cluster. Around 9 p.m., they will be within 2 degrees of each other. Unfortunately, the Moon will be in a waxing gibbous phase, and its brightness may affect the visibility of the Pleiades. Using binoculars is recommended to enjoy this celestial dance as you welcome the arrival of 2026.For more details, please refer to the Taipei Astronomical Museum Website.