The stars of Ophiuchus and Serpens in the star catalogue of Ptolemaios (red; other stars from this catalogue in purple) and in Secunda Classis after precession of the coordinates to the epoch of Ptolemaios/Hipparchos (dark blue; other stars in Classis in light blue). Open black circles are stars from the modern Hipparcos Catalogue. Short solid lines indicate identifications. In many cases stars in Classis are matched by an entry in the star catalogue of Ptolemaios, occasionally by an entry in a different constellation. New stars in Classis, not matched by an entry in Ptolemaios’ catalogue are also seen, including the supernova of 1604, indicated as a blue square near 6,  −14.