Revealing Hitherto Unidentified Ships Among the Graffiti on the Interior Stone Surfaces of the Horologion of Andronikos Kyrristos, Coupling Spectral Imaging Techniques and Digital Tracing

The Horologion of Andronikos Kyrristos, also known as The Tower of the Winds, is an astronomical, cultural and architectural masterpiece of the late Hellenistic period, located on the north side of the foot of the Acropolis hill, in Athens, Greece. Within the frame of the restoration project of the monument all the internal stone surfaces, as well as the external sculpted ones, have been examined using modern spectral imaging techniques, such as hyperspectral imaging and short wave infrared thermography, in order to assist the conservation decisions. The focus was turned to the monument’s internal walls, which are covered by ship graffiti barely observed by naked eye. The present work contributes new information to the documentation of the monument, as new ship graffiti have been revealed through high-resolution images in the visible and infrared monochromatic radiation taken in situ. Furthermore, the digital tracing reproductions of the graffiti after appropriate image processing showed that most of them represent vessels of the recent past (17th–19th century) and the others are simple ship graffiti. The detailed and thorough methodological way with which the vessel depictions were studied, enhanced our knowledge concerning the history of the monument and contributed to the enrichment of its documentation. The new ship graffiti could be interpreted as votive offerings to gods, such as Aeolus and Triton whose names are related to the history of the monument, or votive offerings to Christian saints who are considered protectors of sailors and merchants.