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AIM 

4/20/23 

from not visibly illuminated through partially illuminated to fully illuminated, then back through partially 

illuminated to not illuminated again. There are eight distinct, traditionally recognized stages, called phases. The 

phases designate both the degree to which the Moon is illuminated and the geometric appearance of the 

illuminated part. These phases of the Moon, in the sequence of their occurrence (starting from New Moon), are 

listed in FIG 10

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FIG 10

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Phases of the Moon 

New Moon 

 The Moon’s unilluminated side is facing the Earth. The Moon is not visible 

(except during a solar eclipse). 

Waxing Crescent 

 The Moon appears to be partly but less than one

half illuminated by 

direct sunlight. The fraction of the Moon’s disk that is illuminated is increasing. 

First Quarter 

 One

half of the Moon appears to be illuminated by direct sunlight. The 

fraction of the Moon’s disk that is illuminated is increasing. 

Waxing Gibbous 

 The Moon appears to be more than one

half but not fully illuminated by 

direct sunlight. The fraction of the Moon’s disk that is illuminated is increasing. 

Full Moon 

 

The Moon’s illuminated side is facing the Earth. The Moon appears to be 

completely illuminated by direct sunlight. 

Waning Gibbous 

 The Moon appears to be more than one

half but not fully 

illuminated by direct sunlight. The fraction of the Moon’s disk that is illuminated is 

decreasing. 

Last Quarter 

 One

half of the Moon appears to be illuminated by direct sunlight. The 

fraction of the Moon’s disk that is illuminated is decreasing. 

Waning Crescent 

 The Moon appears to be partly but less than one

half illuminated by 

direct sunlight. The fraction of the Moon’s disk that is illuminated is decreasing. 

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Special Operations