Full Breakdown
Observing the Third Quarter Moon on February 9-10
2/9/2026, 11:44:15 PM
Key Details of the Lunar Event
The third quarter moon, also referred to as the final quarter moon, will rise on February 9, 2023. This celestial event will be visible in the southeast sky late on February 9 and into the early hours of February 10. The precise moment of the third quarter moon phase occurs at 10:48 a.m. EST (1548 GMT), which coincides with daylight hours for observers in North America. Consequently, skywatchers will have the opportunity to view the half-lit moon shortly after midnight on February 10, when it rises alongside bright stars such as Spica and Arcturus.
Observational Highlights
During the third quarter phase, the left side of the lunar disk will be illuminated by sunlight, while the right side remains in shadow. This phase is particularly favorable for telescope users, as it allows for detailed exploration of the moon's surface features. Notable craters such as Herchel, Ptolemaeus, Alphonsus, and Arzachel are ideal targets for observation, with the latter two featuring prominent central peaks that are easily visible through a 9-inch telescope. Additionally, observers can locate the landing sites of the Apollo 12 and Apollo 14 missions above Mare Cognitum, which marked their historic landings over 55 years ago on February 5, 1971.
Lunar Geography and Formation
The third quarter moon phase also presents an opportunity to observe the Montes Appenninus mountain range, located approximately 20 degrees above the lunar equator at the terminator. This 370-mile-long (600-kilometer) range is believed to have formed from an asteroid impact that created the Imbrium impact basin, which subsequently filled with molten lava, resulting in the dark basaltic plain known as the "Sea of Showers."
Official Statements & Responses
The event is being highlighted by various astronomy enthusiasts and organizations, encouraging the public to engage in lunar observation. Recommendations for the best telescopes and binoculars for stargazing are also being shared, along with guides on how to effectively observe the moon.
Verbatim Quotes
- “The third quarter moon is the perfect time to grab your telescope and explore the rims and shadow-lined basins of ancient craters that lie close to the line separating night from day on the lunar disk, known as the terminator.” — Space.com
- “Next, look roughly 20 degrees above the lunar equator at the terminator to witness the curve of Montes Appenninus arcing into the terminator.” — Space.com
Conclusion
The third quarter moon on February 9-10 offers a unique opportunity for both amateur and experienced astronomers to observe and appreciate the lunar surface. With the right equipment, enthusiasts can explore significant geological features and historical landing sites, making this event a noteworthy occasion for skywatchers.
