The European Society for Astronomy in Culture (SEAC) published the proceedings of the SEAC 2018 Conference in Graz under the title “Harmony and Symmetry. Celestial regularities shaping human culture”. The 440-page book is edited by Sonja Draxler, Max E. Lippitsch and Gudrun Wolfschmidt. It contains a contribution by Eberhard Zangger and Rita Gautschy entitled “The Hittite Rock Sanctuary of Yazılıkaya: A Time-Keeping Device from c. 1230 B.C.”. This paper highlights the utilitarian aspects of the Hittite rock sanctuary of Yazılıkaya in central Anatolia with its over ninety rock-cut reliefs of deities, humans, animals, and mythical figures dating to the second half of the thirteenth century B.C. It is shown that the reliefs in Chamber A are arranged in groups for the purpose of displaying the current lunar months, the day of the lunar month, and the year. By marking the days and synodic months, the Hittite priests were able to determine when additional months were required to keep lunar and solar years aligned. Keeping track of time was imperative for the Hittites priests to ensure that the many annual festivals fall into the appropriate seasons.