Which Moon phase appears as a narrow crescent that is decreasing in illumination?

Which Moon phase appears as a narrow crescent that is decreasing in illumination?

• A. Waning Crescent
• B. First Quarter
• C. Full Moon
• D. New Moon

Answer: (A)

When the visible sunlit portion of the Moon is getting smaller, that phase is waning. A crescent shape means only a small sliver is lit, and if that lit part is decreasing, it’s a waning crescent. This phase appears as a thin crescent just before the New Moon, after the Moon has gone through the earlier phases where illumination is growing or has reached full. In contrast, a first-quarter Moon is half-lit and increasing in illumination (waxing), a Full Moon is completely illuminated, and a New Moon is not visible because the Moon is between the Earth and Sun.

When the visible sunlit portion of the Moon is getting smaller, that phase is waning. A crescent shape means only a small sliver is lit, and if that lit part is decreasing, it’s a waning crescent. This phase appears as a thin crescent just before the New Moon, after the Moon has gone through the earlier phases where illumination is growing or has reached full. In contrast, a first-quarter Moon is half-lit and increasing in illumination (waxing), a Full Moon is completely illuminated, and a New Moon is not visible because the Moon is between the Earth and Sun.