Lars Gislén
Biographic Data
| ID | 1440087 |
|---|---|
| NAME | Lars Gislén |
| GIVEN NAMES | Lars |
| FAMILY NAME | Gislén |
| SIGNATURE | GISLÉN L |
| AFFILIATIONS | Lund University |
| ORCID | 0000-0002-6413-2366 |
| VERIFIED | Yes |
| TOTAL WORKS | 14 |
| TOTAL CITATIONS | 0 |
| WORKS AS AUTHOR | 14 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1998 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 0 |
Italic>Peurbach՚S Tabulae Eclypsium
Two of the publications of Thomas Digges on astronomy contain the contradiction that small planetary parallax angles can be measured with a new kind of instrument, but three years later he asserts observational proof of the heliocentric planetary model of Nicholas Copernicus without identifying the new instrument. This assertion rests on the capacity of an instrument to measure angles so small that current instruments like cross-staffs are not eq…
Solar, Lunar and Umbral Sizes in the Al-Khwārizmī and Peurbach Eclipse Tables
We analyze and compare the structure of two tables, the tables of al-Khwārizmī and George Peurbach’s Tabulae Eclypsium , looking at the syzygy angular velocities of the Sun and the Moon and the angular radii of the Sun, the Moon and the lunar eclipse umbra. We show that part of the underlying structure has a mediaeval Indian origin. Finally, we compare recomputed tables with Peurbach’s tables
The Lunar Eclipse in Mexico City on 18 November 1584
The astronomical observations and calculations made at the lunar eclipse of 18 November 1584 in Mexico are analyzed with emphasis on the methods and calculations used. The observations were intended to determine the geographical longitude difference between Mexico City and Seville in Spain but due to several errors, the most important one being using the wrong time for the end of the eclipse in Seville, the longitude difference was incorrect by a…
Analysis of the Horometer Instrument in Peter Apian′s Instrument Buch
The Horometer instrument in Peter Apian′s 1533 Instrument Buch is described and analyzed. This paper is illustrated by several examples of how to manipulate and set up the instrument using the Sun, the Moon and stars to determine time . The paper also contains an Appendix on the mathematics behind its construction
Longitudes, Syzygies, and Instruments in Regiomontanus’ Calendar 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 syzygies. The calendar also contains an instrument fo…
Four Instruments in Martín Cortés’ Breve Compendio De La Sphera and a Rule for Finding the Age of the Moon
This paper investigates and discusses four instruments found in a sixteenth century Spanish book of navigation. The night clock is a rather standard application of similar instruments known since the fourteenth century in Europe. Cortés’ explanation of the causes of the deviation of the magnetic and geographical north is quite original. His instrument to correct for that the Polaris deviates from the North Celestial Pole is an original way of pre…
Analysis of the Tamil Parallax Procedures in Le Gentil's Report of 1776
The Tamil procedures for computing the circumstances of eclipses were reported by the French astronomer Guillaume Le Gentil from his visit to India in the 1760's. This paper investigates these Tamil procedures for a solar eclipse, focusing on the procedures for finding the eclipse parallax which are needed to describe the local appearance of an eclipse. These procedures constitute the essential difference between a solar and lunar eclipse. The pr…
Analysis of the New Moon Times on the Calendar Disk of the Astronomical Clock in Gdansk, Poland
The calendar disk of the fifteenth century astronomical clock in the church of Saint Mary in Gdansk (Poland) contains a wealth of astronomical and calendrical data. We make a statistical analysis of the mean conjunction times of all the mean New Moons as represented on the disk for four Metonic 19-year cycles. We find that the conjunction times were generated using the Alfonsine value for the length of the synodic month and with a mean longitude …
A Hidden Volvelle in Petrus Apianus’ Astronomicum Caesareum
We analyse a volvelle hidden under the top disks of one of the volvelles in Petrus Apianus’ Astronomicum Caesareum . It turns out that this volvelle, completed with an overlay disk with the ecliptic, can be used to compute the rising and setting signs in the zodiac given the latitude of a locality, the longitude of the Sun, and the hour of the day. It is based on a standard stereographic projection normally used for astrolabes but the volvelle in…
Showcasing Seventeenth-Century Jesuit Astronomy in Asia
The first great ruler to encourage the adoption of Western culture and technology throughout Siam was King Narai, who also had a passion for astronomy. He showed this by encouraging French and other Jesuit missionaries, some with astronomical interests and training, to settle in Siam from the early 1660s. One of these was Father Antoine Thomas, and he was the first European known to have carried out scientific astronomical observations from Siam,…
Seventeenth Century French Jesuit Longitude Determinations in Asia
Two methods of setting clocks to show correct time during the 17th century by French Jesuits in China are investigated and their computations and accuracy are analysed. These methods were used to rectify the clocks used for timings of eclipses of the Galilean moons or for lunar eclipses that in turn were used to determine geographical longitudes by Jesuit missionaries in Siam and China. It is found that the calculations needed, in spite of being …
Medieval Astronomical Clocks in the Baltic Region and the Mysterious Golden Numbers in Gdansk
Large medieval clocks were built in a number of Hanseatic towns in the Baltic region from the end of the fourteenth century to the middle of the fifteenth century. Several factors contributed to their building: there was a need for public display of time in the rapidly growing medieval towns, the technique of constructing mechanical clocks became available with the invention of the verge escapement in Italy in the second half of the of the thirte…
Early Javanese Inscriptions
Even the historical expert is - understandably - terrified by the complications involved in the calculation of dates. Early Javanese Inscriptions puts the study of Indonesian epigraphical dating on a completely new footing, both in speed and in reliability. It examines the early Javanese inscriptions, taking account for the first time of the detailed astronomical information so routinely presented in the texts. A computer analysis, (see http://ww…
The Whole Moon was Eaten”
One might classify earthquakes and volcanic eruptions as “natural disasters”, whereas comets and eclipses might be described merely as “natural curiosities”. In earlier times, however, all were equally frightening, signs that the gods were angry. A form of protection against eclipses was available, however, in the sense that prediction provided a means of countering the event. Consequently one main function of the astronomer/astrologer (hencefort…
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The Whole Moon was Eaten”
One might classify earthquakes and volcanic eruptions as “natural disasters”, whereas comets and eclipses might be described merely as “natural curiosities”. In earlier times, however, all were equally frightening, signs that the gods were angry. A form of protection against eclipses was available, however, in the sense that prediction provided a means of countering the event. Consequently one main function of the astronomer/astrologer (hencefort…
Early Javanese Inscriptions
Even the historical expert is - understandably - terrified by the complications involved in the calculation of dates. Early Javanese Inscriptions puts the study of Indonesian epigraphical dating on a completely new footing, both in speed and in reliability. It examines the early Javanese inscriptions, taking account for the first time of the detailed astronomical information so routinely presented in the texts. A computer analysis, (see http://ww…
Medieval Astronomical Clocks in the Baltic Region and the Mysterious Golden Numbers in Gdansk
Large medieval clocks were built in a number of Hanseatic towns in the Baltic region from the end of the fourteenth century to the middle of the fifteenth century. Several factors contributed to their building: there was a need for public display of time in the rapidly growing medieval towns, the technique of constructing mechanical clocks became available with the invention of the verge escapement in Italy in the second half of the of the thirte…
Showcasing Seventeenth-Century Jesuit Astronomy in Asia
The first great ruler to encourage the adoption of Western culture and technology throughout Siam was King Narai, who also had a passion for astronomy. He showed this by encouraging French and other Jesuit missionaries, some with astronomical interests and training, to settle in Siam from the early 1660s. One of these was Father Antoine Thomas, and he was the first European known to have carried out scientific astronomical observations from Siam,…
Seventeenth Century French Jesuit Longitude Determinations in Asia
Two methods of setting clocks to show correct time during the 17th century by French Jesuits in China are investigated and their computations and accuracy are analysed. These methods were used to rectify the clocks used for timings of eclipses of the Galilean moons or for lunar eclipses that in turn were used to determine geographical longitudes by Jesuit missionaries in Siam and China. It is found that the calculations needed, in spite of being …
Analysis of the New Moon Times on the Calendar Disk of the Astronomical Clock in Gdansk, Poland
The calendar disk of the fifteenth century astronomical clock in the church of Saint Mary in Gdansk (Poland) contains a wealth of astronomical and calendrical data. We make a statistical analysis of the mean conjunction times of all the mean New Moons as represented on the disk for four Metonic 19-year cycles. We find that the conjunction times were generated using the Alfonsine value for the length of the synodic month and with a mean longitude …
A Hidden Volvelle in Petrus Apianus’ Astronomicum Caesareum
We analyse a volvelle hidden under the top disks of one of the volvelles in Petrus Apianus’ Astronomicum Caesareum . It turns out that this volvelle, completed with an overlay disk with the ecliptic, can be used to compute the rising and setting signs in the zodiac given the latitude of a locality, the longitude of the Sun, and the hour of the day. It is based on a standard stereographic projection normally used for astrolabes but the volvelle in…
Analysis of the Tamil Parallax Procedures in Le Gentil's Report of 1776
The Tamil procedures for computing the circumstances of eclipses were reported by the French astronomer Guillaume Le Gentil from his visit to India in the 1760's. This paper investigates these Tamil procedures for a solar eclipse, focusing on the procedures for finding the eclipse parallax which are needed to describe the local appearance of an eclipse. These procedures constitute the essential difference between a solar and lunar eclipse. The pr…
Analysis of the Horometer Instrument in Peter Apian′s Instrument Buch
The Horometer instrument in Peter Apian′s 1533 Instrument Buch is described and analyzed. This paper is illustrated by several examples of how to manipulate and set up the instrument using the Sun, the Moon and stars to determine time . The paper also contains an Appendix on the mathematics behind its construction
Longitudes, Syzygies, and Instruments in Regiomontanus’ Calendar 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 syzygies. The calendar also contains an instrument fo…
Four Instruments in Martín Cortés’ Breve Compendio De La Sphera and a Rule for Finding the Age of the Moon
This paper investigates and discusses four instruments found in a sixteenth century Spanish book of navigation. The night clock is a rather standard application of similar instruments known since the fourteenth century in Europe. Cortés’ explanation of the causes of the deviation of the magnetic and geographical north is quite original. His instrument to correct for that the Polaris deviates from the North Celestial Pole is an original way of pre…
Solar, Lunar and Umbral Sizes in the Al-Khwārizmī and Peurbach Eclipse Tables
We analyze and compare the structure of two tables, the tables of al-Khwārizmī and George Peurbach’s Tabulae Eclypsium , looking at the syzygy angular velocities of the Sun and the Moon and the angular radii of the Sun, the Moon and the lunar eclipse umbra. We show that part of the underlying structure has a mediaeval Indian origin. Finally, we compare recomputed tables with Peurbach’s tables
The Lunar Eclipse in Mexico City on 18 November 1584
The astronomical observations and calculations made at the lunar eclipse of 18 November 1584 in Mexico are analyzed with emphasis on the methods and calculations used. The observations were intended to determine the geographical longitude difference between Mexico City and Seville in Spain but due to several errors, the most important one being using the wrong time for the end of the eclipse in Seville, the longitude difference was incorrect by a…
Italic>Peurbach՚S Tabulae Eclypsium
Two of the publications of Thomas Digges on astronomy contain the contradiction that small planetary parallax angles can be measured with a new kind of instrument, but three years later he asserts observational proof of the heliocentric planetary model of Nicholas Copernicus without identifying the new instrument. This assertion rests on the capacity of an instrument to measure angles so small that current instruments like cross-staffs are not eq…
Historical Astronomy and Related Studies (12 works) · Historical Geography and Cartography (7 works) · Geography (6 works) · History (6 works) · Physics (6 works) · Astronomy (5 works) · History and Developments in Astronomy (5 works) · Ancient history (4 works) · Eclipse (4 works) · Longitude (4 works)