I.C.R.A. Network - Stellae Laetatae Sunt

Stellae Laetatae Sunt

Le ellissi meridiane dei Giubilei - The meridian ellipses of the Jubilees

Basilica di S. Maria degli Angeli e dei Martiri, Roma

Dal 20 Marzo 2025

The ellipses of the Polaris, calculated for the series of the Jubilee years, starting from 1700 to 2500, are a unique masterpiece of science, history and art. The baricenter of the ellipses is the Celestial North Pole, and its altitude above the Northern horizon is the local latitude. The value 41°54'30" inscripted among the ellipses includes the relativistic effect of the stellar aberration of the Polaris on the 1st January 1701. Bianchini could not know this effect, since it was discovered 26 years later by James Bradley, but he was very accurate in measuring the stellar positions with its influence. The minimum distance to the Celestial North Pole will occur in 2100, so Bianchini exploited this fact to represent in concentrical ellipses the holy years symmetrical to 2100, starting from 1700 which was closed by the pope Clement XI, the same who financed the meridian line. The forthcoming "mathematical" jubilees are represented with simple golden lines, while the secular ones with starred golden lines, containing the Polaris each hour of the day/night. The total of 800 years encompasses two complete Gregorian cycles, after which the tropical year is in perfect agreement with the civil and religious year. The fundamental stages of the Catholic Church history related with the Jubilees dates are presented, also for the three Jubilee not celebrated (1800-1850 and 1875) because the political situation did not permit them. In parallel are shown the stages of the History of Astronomy in Rome. This exhibit has been prepared for the Jubilee of 2025.

Prefacio