This article, the second part of a series, details the reconstruction and ongoing maintenance of the meridian line in the Basilica of San Petronio, Bologna. It describes Eustachio Zanotti's 1776 restoration, which aimed to retain Cassini's original dimensions while improving stability with new materials. The article highlights the meridian's function in accurately determining the vernal equinox and its use for astronomical observations and calendar correction. It also covers Federigo Guarducci's 1904 inspection confirming the instrument's excellent preservation and stability, and discusses an adjacent 1758 mechanical "equation clock" used to reconcile true solar time with mean time.
Dials: Noon Lines,
Historical Dials