GEOMETRIE LUMINOSE NELLA CHIESA DI SAN NICOLA DA MYRA A MOTTOLA / GEOMETRIES OF LIGHT IN THE CHURCH OF ST. NICHOLAS FROM MYRA IN MOTTOLA

ABSTRACT The San Nicola (or St. Nicholas, or Saint Nicholas) rock church is located by the city of Mottola (TA). It’s well known both for its rich frescoes and for the occurrence of a hierophany connected to the fresco of St. Nicholas of Myra, on March 15th and September 29th. Both dates are extremely symbolic: as a matter of fact, the saint was born on March 15th 270 a.C., while, on September 29th , his mortal remains were placed in the Basilica of Bari. The hierophany consists of a luminous ellipse that appears every year in these days on the blessing hand of the saint, thanks to the light passing through a small hole in the facade. Due to an integrated survey, we obtained a digital 3d model with high definition textures in which we simulated all the luminous phenomena that can occur in the church, depending on the east-west orientation. We discovered other two minor hierophanies, also occurring on symbolic dates. The first concerns St. Leonard, whose fresco is located on the first pillar on the right side of the entrance: sunlight casts a luminous ellipse on the saint's chest at sunset on November 6th, the anniversary of his birth. The second occurs during the anniversary of another saint birth: the luminous ellipse touches the fresco of St. John at sunset on September 14th. Keywords: archeoastronomy, hierophany, san nicola, mottola, geometry of light, photogrammetric survey