The iron gnomon, now broken off at the base, is held in place by a lead adhesive. A permanent glass covering makes modern measurement impossible. The figures at left were obtained from Grablovitz´ early publication and recent photographs. These researched and calculated results compare favorably with measurements taken from a plaster cast of the dial displayed in the Museo della Civitá romana. The windrose surrounding the dial is inscribed in Latin. Both inscriptions, the eleven hour lines and three day curves are emphasized by a black coloring which may not be original.
This object has not been measured by the 3D pipeline. Its entry in the catalogue rests on the published description only; no surface fit, latitude or line detection exists for it.