When the moon is shown as a cresent , half moon , etc. , it is because the 2 different hemispheres of Earth are looking at different , illuminated parts of the moon . So , astronomers ( people who look at the sky ) in the Northern Hemisphere may see a Waxing Gibbous , but people in the Southern Hemisphere will look up and probably see a Waxing Crescent . In the northern hemisphere , if the left side of the Moon is dark then the light part is growing , and the Moon is referred to as waxing ( moving towards a full moon ) .