Astronomical documentation was used by the Mayans for a variety of purposes, such as determining their calendar systems, ritual schedules, and agricultural cycles. The three main codices contain charts, tables, and diagrams of mathematics and writing relating to different celestial bodies. Images of gods and astrological beings are connected to the data by symbolizing these objects (ex. Kinich Ahau/"God G," the sun god), their cycles, or other concepts related to them.
The Madrid Codex is one of the three folio codices dated to the Postclassic Period. It primarily contains almanacs and astrological information used by priests in their ritual work. This page in particular has a depiction of what has been interpreted as an astronomer. They are shown with blue skin sitting in the center and top of the page, observing the cycle of a celestial body that is surrounding them.
These pages are from a second document, the Paris Codex. They are notable for the reversal of the script, indicating they should be read from right to left. They also making interesting use of the "kin" or winged glyph. Zodiacal beings are depicted in two horizontal registers per page, each holding a "kin" glyph above them (in the celestial band). This can be interpreted as the beings flying west, a nod to the westward precession of equinoxes in relation to the fixed stars. This is an example of the level of detail in these codices, where every variation has a utility.
A third and most well known Postclassic document is the Dresden Codex. It contains extensive mathematics (numbers consist of variations of lines and dots) and astronomical tables, including the middle panel of this page, a part of the Mars table. This is a documentation of the synodic (return of a celestial object to the same position in relation to the Sun and the observer on Earth) and sidereal (return to the same position in relation to fixed stars) cycles of Mars.
This page is one of several that make up the Venus Table of the Dresden Codex. The page's text is divided into calendar dates at the top (specifically dates from the "Tzolk'in" calendar, more on the next page) and calculated totals and intervals in the middle and bottom of the text block. The table uses calendar dates and astronomical observations to track the complexities of Venus' movements. The gods depicted alongside the text represent different aspects of the planet.