Webpages on the History of Astronomy
by Robert Harry van Gent

The following webpages reflect my current interests in the history of astronomy, history of astrology, history of celestial cartography and the history of calendars and timekeeping.
Flemish tapestry (Doornik?, c. 1500-1515) depicting the muse Astronomia with an astronomer (Claudius Ptolemy?), a scribe and shepherds gazing in awe at the heavens (Röhsska Museet för Konsthantverk och Design, Göteborg).

Webpages in Dutch

• Astronomie, Astrologie en Tijdrekenkunde in de Middelnederlandse Artes-Literatuur
• ‘De Hemelse Wetten’: Een cultuurgeschiedenis van de sterrenkunde (HOVO cursus)
• De Islamitische Tijdrekening
• De Wettelijke Tijdregeling in Nederland (met een overzicht van de zomertijden sinds 1916)

Webpages in English

Calendars, Chronology, Timekeeping

• Calendrical Tobacco Boxes by Pieter Holm
• A Catalogue of Eclipse Cycles (under construction)
• Delta T: Approximate Algorithms for Historical Periods (temporarily unavailable for revision)
• Determining the Sacred Direction of Islam
• A History of the International Date Line
• Islamic-Western Calendar Converter (based on the tabular Islamic calendar)
• The Mathematics of the ISO 8601 Calendar
• A Perpetual Easter and Passover Calculator (with an extensive bibliography)
• Predicting the First Visibility of the Lunar Crescent
• The Islamic Calendar of Turkey
• The Umm al-Qura Calendar of Saudi Arabia

Celestial Cartography

• Historical Celestial Atlases on the Web
• Historical Globes of the Red Planet
• Andreas Cellarius (c. 1596-1665): A Bio-Bibliographical Study
• A Curious Dutch Lunar Map
• The Atlas Coelestis (1742) of Johann Gabriel Doppelmayr (under construction)
• A Puzzling Pair of Star Maps and Two Unknown Constellations

History of Astronomy

• Ancient Luni-Solar & Planetary Ephemerides (under construction)
• Bibliography of Mesopotamian Astronomy and Astrology (under construction)
• Ceramic Comets (Halley’s Comet in 1910)
• Early Dutch-German Altitude Sundials
• Historical Telescopes in the Netherlands (and where to see them)
• Internet Bibliographies on the History of Astronomy and Astronomical Instruments
• Isaac Newton and Astrology
• Magnetic Declination Maps for Historical Epochs (under construction)
• Out of Old Books: Essays on the History of Astronomy by Helen Sawyer Hogg
• Star of Bethlehem Bibliography (under construction)
• Transit of Venus Bibliography (under construction)

About Myself

My Publications