Moon Phases

Moon Phases is written using Java. You must have a Java enabled browser such as Firefox to be able to see this applet.

Google Chrome Users: Note that Goolge Chrome Version 42 and later requires an additional configuration step to continue using NPAPI (Java) plugins.

1. In your URL bar, enter:
2. Click the Enable link for the Enable NPAPI configuration option.
3. Click the Relaunch button that now appears at the bottom of the configuration page.

Still not working? Please email us.

In this program, I use a number that corresponds to the Moon phase:

Phase Name
0.00 Full Moon
0.00-0.25 Waning Gibbous Moon
0.25 Last Quarter Moon
0.25-0.50 Waning Crescent Moon
0.50 New Moon
0.50-0.75 Waxing Crescent Moon
0.75 First Quarter Moon
0.75-1.00 Waxing Gibbous Moon
1.00 Full Moon (again)

"Waxing" means growing and "waning" means shrinking. One appropriate definition of "gibbous" is "swollen on one side."

Notice the solar eclipse at phase 0.50!!! In reality, the Moon's orbit is slightly tilted, so solar eclipses are rare, not every month. Try a phase of 0.5001 for a cool view of an eclipse (be sure to use Earth View).