26b.

Source: WTL© digital photographs (2008) taken on site in the Mundo Perdido area of Tikal.
Comments: This series of three photographs illustrates three buildings the Maya used for solar observations. One of the Maya's calendar years was of 365 days; with these three buildings, they calculated the precised days of the two equinoxes and the two solstices per year. When the sun struck an altar in the building in #26a it indicated the winter solstice, the shortest day of the year. The building in the middle, #26b, indicated both the autumnal and spring equinoxes. And, when the sun was in position to indicate the year's longest day, the building on the right, #26c, would signal the vernal solstice. For a chart of how the Maya calculated time and Maya terminology relating to time, see: => Maya Region Notes.