Although graphical methods are in common use by engineers and astronomers, they are less familiar to archaeologists. To portray the rhythm of celestial motions, astronomers often use “elongation” diagrams to show angular distances of moon and planets from the sun on each day of the calendar year.

The Maya recognized a zone within which the planets could not be seen because of proximity to the brilliant disk of the sun. The moon cannot be seen on the day of conjunction with the sun, and is generally invisible on the day before and the day after this “new moon day.” The three consecutive days in the lunar table of the Dresden Codex may represent the 3-day phase of moon disappearance.