A waxing gibbous moon is an intermediate phase of the lunar cycle that starts right after the first quarter moon and lasts until it becomes a full moon.
Meaning of a waxing gibbous moon
A waxing gibbous moon consists of two terms: waxing and gibbous.
“Waxing” means increasing or growing. After a first quarter moon, the illuminated area of the moon increases day by day until it becomes a full moon. That’s why it’s called a waxing moon.
The illuminated area of a waxing gibbous moon increases from 50% to 100%.
“Gibbous” comes from a Latin word, “gibbosus,” that means “hump-backed.” The moon looks like a hump-backed or convex shape between a first quarter moon and a full moon. That’s why it’s called a gibbous moon.
So a waxing gibbous moon indicates the shape of the moon.
Rise and set time of a waxing gibbous moon
A waxing gibbous moon rises in the afternoon (between noon and sunset), reaches its highest point in the sky (overhead point) in the evening, and sets after midnight (between midnight and sunrise).
Please remember, a waxing gibbous moon does not rise and set at the same time every day. On consecutive days, a waxing gibbous moon rises and sets about 50 minutes later.
Best time to see a waxing gibbous moon
You’ll find a waxing gibbous moon high in the evening sky around two to three days after a first quarter moon.
A waxing gibbous moon is easily visible in the afternoon, as the sunlight reflected from it is bright enough to be seen against the daytime blue sky.
Duration of a waxing gibbous moon
The moon takes about 29.5 days to complete a lunar cycle.
Now, a lunar cycle has eight phases in total. These are the new moon, waxing crescent moon, first quarter moon, waxing gibbous moon, full moon, waning gibbous moon, third quarter moon, and waning crescent moon.
Four primary phases (new moon, first quarter, full moon, and third quarter) have no duration as they occur at a specific moment in time.
So the duration of four intermediate phases (waxing crescent, waxing gibbous, waning gibbous, and waning crescent) is 29.5 days in total.
So the duration of a waxing gibbous moon is about 29.5/4 = 7.38 days.
Orientation of a waxing gibbous moon
A waxing gibbous moon appears more than half-illuminated but less than full in the sky from anywhere in the world. Its percentage of illumination is also the same. However, it looks opposite in opposite hemispheres.
In the Northern Hemisphere, the illuminated part appears on the right side, and in the Southern Hemisphere, it appears on the left side.
The Golden Handle on a waxing gibbous moon
The Golden Handle (a bright arc) is visible on the lunar terminator (lunar day-night boundary) when the yellowish sunlight reflects from the peak of Montes Jura (a mountain range), while Sinus Iridum (a bay) is still in darkness.
It is an optical feature on the lunar surface, visible through a pair of binoculars or a telescope about 3 days after a first quarter moon.
The phases of the moon
The moon goes through phases as it orbits Earth. Follow the links below to understand the phases of the moon.
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