Th is article is dedicated to a special category of structures that may be called “astronomical instruments”, constructed in the Inca Empire (ca. 14-16 c. AD). As mentioned in some sources, these were intended for use by a small group of priests-astronomers. A good example is Intimachay in Machu Picchu, which was recently re-designated as an astronomical observatory, far more complex and precise than was previously believed. Th e discovery of Inkaraqay – El Mirador, a second structure, even more complicated than Intimachay and erected for the purpose of precise astronomical observation, confi rms the importance of the knowledge of the skies in the running of the Incan Empire.