This Python 3 script is designed to work with Argos, a wonderful GNOME 3 shell extention that allows for the easy creation of new extentions. This program finds the users location with freegeoip.net and uses that to find the current moon phase with Astronomical Applications API. The resulting moon phase is displayed as an emoji in the user's GNOME menu bar. Clicking on the emoji creates a dropdown that displays the name of the current phase, as well as the percent of the moon illuminated.
Make sure Argos is installed and working properly in your GNOME 3 installation. The install link can be found here here. All that is needed to add this plugin is to download MoonPhase.4h.py and place it in the ~/.config/argos folder. For example, if the Python file is located in the Downloads folder, the user could run cp MoonPhase.4h.py ~/.config/argos.