The building has a roughly pentagonal outline and it is skewed 45% in orientation from the remainder of the buildings at the site by many degrees. The building is oddly shaped, and its shape been variously described as a baseball diamond, home plate, or arrowhead. Low relief carvings on the building include a crossed-sticks glyph, thought to represent astronomical symbols.
In addition to its remarkable exterior outline, it has a horizontal tunnel cut through it, and an outer staircase that's skewed another few degrees from the direction of the door.
Building J's architectural orientation is thought by researchers to point to the location of the star Capella. Capella is indicated by the orientation point of the building on May 2, when the sun reaches its zenith and passes directly overhead.
Sources
There are more ancient observatories to read about; and more about Monte Alban and the Zapotecs as well.
Aveni, Anthony. 2001. Building J at Monte Alban. pp 262-272 in Skywatchers: A Revised and Updated Version of Skywatchers of Ancient Mexico. University of Texas Press, Austin.
Peeler, Damon E. and Marcus Winter 1995 Building J at Monte Alban: A correction and reassessment of the astronomical hypothesis. Latin American Antiquity 6(4):362-369.
This glossary entry is part of the Dictionary of Archaeology.
