How Moon Phases

Phases of the Moon

As our moon travels through space orbiting our planet, we see it in its different phases at different times and if you mouseover the graphic small moons arranged around the earth in the picture below left you will get an explanation for what you see in the box on the right....

Thanks to Pete Lawrence for the lunar images DigitalSky.org

Moon Phases and Time of Day

Phase	Rises	In Eastern Sky	Highest	In Western Sky	Sets
New	~sunrise	morning	noon	aftermoon	~sunset
Waxing Crescent	just after sunrise	morning	just after noon	aftermoon	just after sunset
First Quarter	~noon	afternoon	~sunset	night(pm)	~midnight
Waxing Gibbous	afternoon	~sunset	night(pm)	~midnight	night(am)
Full	~sunset	night(pm)	~midnight	night(am)	~sunrise
Waning Gibbous	night(pm)	~midnight	night(am)	~sunrise	morning
Third Quarter	~midnight	night(am)	~sunrise	morning	noon
Waning Crescent	just before sunrise	morning	just before noon	aftermoon	just before sunset
Waning Crescent	KEY: times in grey indicate that the moon is not visible

When is the Moon Visible

Many people seem to expect that the moon rises at night and sets before daylight - perhaps a hangover from all those pictures in our children's story books where the moon is always there at night and never in the day!

The table above shows how the moon phases cycle in time as well as illumination for the surface of the moon.

Tracking these changes can be an exciting and interesting project to set in school.

There is a lot of interest in discovering just how soon we can see the new crescent moon - some very experienced observers can see the moon within 24 hours of it being new, but care must be taken as the new moon is so close to the sun that all the usual caveats and warnings for observing (or more to the point, NOT observing) the sun apply here as well.