Abstract
This article discusses a gloss fragment of the Huichapan Codex (17th Century) that appears to make reference to a mathematical formula for calculating and/or counting eclipses. The gloss is analyzed in terms of the Mesoamerican calendar models, the idea that otomí astronomers were avid moon cycle followers and, finally, in accordance to the internal chronologic structure of the actual codex and the eclipses in it registered.
