Instructions

• You can print the calendar simply by selecting the 'Print' feature of your browser. 'Print Preview' will show what the printed version will look like before printing.
• The
  
  reset button sets the date to the current month.
• The
  
  settings button allows adjustment of various display, time, and location parameters. Changes take place immediately, but revert to their previous values if 'Cancel' is selected. If 'Ok' is selected, the changes will be retained on future visits to this page.
  • Tooltips: Hovering over any day on the calendar can display a tooltip with information on the moon on that date. This control lets you turn tooltips on or off.
  • Legend: Turn the legend at the bottom of the calendar, showing the phase symbols and the type of calendar used, on or off.
  • Position Angle: the moon's bright limb normally makes an angle with the north-south meridian it it lies on. This control chooses whether to render the moon at this angle, or not.
  • North/South Up: Determine whether the moon is rendered with its northern or southern edge up. The former rendering will give an appearance more familiar to those in the northern hemisphere, while the latter will be more appropriate for those in the southern hemisphere. Viewers near the equator can choose whichever seems most appropriate. The legend symbols for the quarter moons also flip.
  • 24/12 Hour Time Format: Controls the format of times displayed in the tooltips.
  • First Day of Week: Redraws the calendar with the selected day in the first column.
  • Language: Renders the month, day, and in some cases the numerals of the calendar in the language chosen, both on the calendar itself, and on the tooltips. Note that this is dependent on your computer having the correct fonts installed; if not, these elements may render as empty blocks.
  • Scaling: Adjust the scale at which each day's drawing is rendered. 'None' will draw all phases at the same size; 'Normal' will draw them to scale as they appear in the sky, as the moon moves nearer and farther away in its orbit; 'Exaggerated' will amplify this distance scaling to make it more apparent.
  • Phase Times: Select the time at which the displayed phases are calculated. 'Local Midnight' and 'Local Time' use the timezone your computer is set to when determining these times, while 'UTC Midnight' will calculate them as they appear at midnight UTC, or GMT.
  • First Date in Gregorian Calendar: The Gregorian calendar replaced the Julian calendar to correct for misalignment with the seasons in October 1582. Actual adoption of the Gregorian calendar, however, varied considerably in different countries and regions. You can set the first date of the Gregorian calendar to whatever you like, on or after October 15, 1582. The setting is fairly flexible and accepts several formats, but YYYY-MM-DD is recommended if errors occur. Note that a number of days will be missing prior to the date chosen, depending on when the changeover occurs, in order to make up for the accumulated misalignment.