Longitudes, Syzygies, and Instruments in Regiomontanus' Calender for 1475-1531
Instruments and tables in Regiomontanus’ calendar published in 1474 are analysed and explained. It is shown that Regiomontanus used the Alfonsine Tables corrected for the longitude time difference between Toledo and Nuremberg. It is also shown that for the syzygy and eclipse times he used apparent solar times. The syzygy tables of George Peurbach may have been used to correct from mean to true syz