The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

lars gislen

Lars Gislén

Retired, affiliated researcher

lars gislen

Longitudes, Syzygies, and Instruments in Regiomontanus' Calender for 1475-1531

Author

  • Lars Gislén

Summary, in English

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 syzygies. The calendar also contains an instrument for converting between equal and unequal times, a volvelle for finding the true longitude of the Moon, a quadrant tool for the construction of a horizontal sundial, and a universal vertical sundial. The construction and workings of these instruments are analysed.

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 syzygies. The calendar also contains an instrument for converting between equal and unequal times, a volvelle for finding the true longitude of the Moon, a quadrant tool for the construction of a horizontal sundial, and a universal vertical sundial. The construction and workings of these instruments are analysed.

Department/s

  • Particle and nuclear physics

Publishing year

2024

Language

English

Pages

91-104

Publication/Series

Journal of Astronomical History and Heritage

Volume

27

Issue

1

Document type

Journal article

Publisher

National Astronomical Research Institute of Thailand

Topic

  • Astronomy, Astrophysics and Cosmology

Status

Published

ISBN/ISSN/Other

  • ISSN: 1440-2807