On September 11, 2025, the Moon will be in a Waning Gibbous phase. Its illuminated surface will be approximately 89% visible from Earth. This phase occurs in the lunar cycle three days after the Full Moon. Astronomically, the Moon will be located in the zodiacal constellation of Pisces.
The term Waning Gibbous describes the Moon as it transitions from full illumination toward the Third Quarter phase. "Waning" signifies that the visible illuminated portion is decreasing each night, while "gibbous" indicates that the shape is larger than a semicircle but smaller than a full circle. On this date, the Moon will rise in the late evening, traverse high across the sky after midnight, and set in the west after sunrise the following morning. The precise rise and set times are dependent on the observer's specific geographic coordinates.
For observational purposes, the Moon's significant brightness during this phase will make it a prominent object in the night sky. However, this high level of illumination, often referred to as moonlight or lunar glare, will create challenging conditions for viewing fainter celestial objects. The ambient light will obscure deep-sky phenomena like nebulae, star clusters, and distant galaxies, making the date less than ideal for serious astrophotography or stargazing that requires dark-sky conditions.
