An Astronomical Instrument in Stone
The Intihuatana stone is a precise astronomical instrument carved directly from the bedrock at the highest point of Machu Picchu. Its name is a combination of the Quechua words 'inti' (sun) and 'wata-' (to tie or hitch), translating to "hitching post of the sun." This name shows its function in Inca cosmology: to symbolically tether the sun and ensure its orderly passage through the sky, which was essential for their agricultural calendar.
The stone's primary function is linked to the equinoxes. Around March 21 and September 21, the sun at midday is positioned almost directly above the pillar, causing it to cast no discernible shadow. This event signaled a moment of celestial balance for the Inca. The stone also tracks the solstices. On the June solstice (winter in the Southern Hemisphere), the gnomon casts its longest shadow to the south, while on the December solstice, it casts a much shorter shadow to the north. The corners and faces of the polyhedron are carefully carved to align with the four cardinal points, further showing its function as a solar clock. Some alignments also correspond with sacred mountain peaks, such as the December solstice sunset azimuth aligning with the summit of Pumasillo mountain.