  The page written by the astronomer Francesco Bianchini (1662-1729) and
containing the data of the 1701 winter solstice observed at Santa Maria degli
Angeli is presented for the first time in figure 2 and widely discussed along
this paper. The great meridian line in the Basilica of Santa Maria degli Angeli
in Rome was built in 1701/1702 with the scope to measure the Obliquity of the
Earth's orbit in the following eight centuries, upon the will of pope Clement
XI. During the winter solstice of 1701 the first measurements of the obliquity
have been realized by Francesco Bianchini, the astronomer who designed the
meridian line, upgrading the similar instrument realized by Giandomenico
Cassini in San Petronio, Bononia. In this paper the accuracy of the data
observed by Francesco Bianchini is discussed and compared with up-to-date
ephemerides. The modern situation of this historical instrument is also
presented.
