AI – ‘In antiquity, a cosmograph (from Greek kosmos “world/cosmos” and grapho “to write/draw”) was not a single, universally standardized item, but rather a functional term for instruments or diagrams designed to map, simulate, and describe the structure and movements of the cosmos as understood at the time. 

The most prominent example of an ancient cosmograph is the Antikythera Mechanism (c. 2nd century BC), which functioned as a complex, hand-cranked, geared, analog computer. 

The primary functions of these devices in antiquity included:

• Astronomical Simulation (Orrery): They modelled the motions of the solar system, specifically tracking the positions of the sun, moon, and the five planets known to the Greeks.
• Predicting Celestial Cycles: They calculated complex, long-term cycles, including the 19-year Metonic cycle, the 76-year Callippic cycle, the 18-year Saros cycle, and the 54-year Exeligmos cycle.
• Predicting Eclipses: The devices could forecast the timing, characteristics, and possibility of solar and lunar eclipses years in advance.
• Calendar and Time Tracking: They aligned lunar months with solar years and marked the timing of major pan-Hellenic athletic games, such as the Olympics.
• Educational/Philosophical Device: They served as a “philosopher’s guide to the galaxy,” used to demonstrate the cosmos and humanity’s place within it.
• Astrological/Delineation Mapping: In some contexts (e.g., in early Chinese tradition), a cosmograph (specifically the shi or “diviner’s board”) was used to map celestial movements against terrestrial points for divination or to determine auspicious times.’ 

My next Q. – ‘In antiquity were glyph stones ever used as cosmographs?’

AI – ‘Yes, in antiquity, various cultures frequently used glyph stones, stelae, and rock carvings as cosmographs—physical representations or maps of their perceived universe, cosmos, and time cycles. These stones served to bridge the gap between the mortal world, nature, and the divine by organizing celestial and earthly knowledge into a fixed, sacred space. Examples of Ancient Glyph Stones as Cosmographs

• Aztec Calendar Stone (Stone of the Five Suns): This 24-ton basalt monolith is a premier example of a cosmogram, featuring the sun god Tonatiuh surrounded by glyphs that map out the Aztec understanding of time, creation, destruction, and the cosmos.
• Maya Stelae and Altars: Maya civilization used carved stone slabs (stelae) and round altars to record astronomical data, calendar cycles, and the cosmos, often linking rulers to divine, cosmological events. These stones were often placed in sacred spaces to function as portals to the gods.
• Neolithic Passage Graves (Newgrange, Ireland): Engraved stones within these, such as spirals and concentric arcs, are interpreted as representations of celestial cycles and spiritual journeys dating back to 3200 BCE.
• Petroglyphs and Geoglyphs: Across the globe, from the American Southwest to Siberia, petroglyphs (carved stone) and geoglyphs (ground drawings) encoded astronomical, energetic, and spiritual information, sometimes acting as early star maps.
• Aniconic Stelae: In some ancient Near Eastern and Greco-Roman traditions, plain or minimally carved steles were used to demarcate the presence of a deity, serving as a symbolic focal point for understanding the divine structure. 

Purpose and Meaning
These stones were more than decorations; they were “keys” to understanding the cosmos, often detailing: 

• Cycles of Time: Solar, lunar, and Venusian cycles.
• Sacred Geography: Alignment with specific, ritual, or celestial spots.
• Mythological Narratives: Stories of creation and the order of the universe.’