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Physics & Astronomy International Journal

Opinion Volume 4 Issue 5

References of Halley’s Comet at the Royal Observatory of Cádiz (Spain)

David Almorza- Salas,1 David Almorza Gomar2

1Instituto y Observatorio de Marina San Fernando (Cádiz, Spain), Spain
2Department of Statistics and Operational Research, University of Cádiz (Spain), Spain

Correspondence: David Almorza-Salas, Department of Statistics and Operational Research, University of Cádiz (Spain),Spain, Tel +34-686104252

Received: August 31, 2020 | Published: September 25, 2020

Citation: Almorza-Salas D, Almorza-Gomar D. References of Halley’s Comet at the Royal Observatory of Cádiz (Spain). Phys Astron Int J. 2020;4(5):169-170. DOI: 10.15406/paij.2020.04.00217

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In this paper we include the references of the participation of the Royal Observatory of Cádiz (Spain), through the astronomer Louis Godin, to the study of Halley’s comet during 1759. As a new goal we incorporate a reference of the astronomer Charles Messier in 1765 that had not been registered.

Keywords: halley’s comet, godin, delisle, royal observatory of cádiz


Halley’s comet returns to the inner Solar System every 75-80 years. The late Babylonian texts in the British Museum are shown to contain probable observations of Halley’s comet at both this 164 BC and 87 BC apparitions. There are also two possible Chinese references in 87 BC and 240 BC.1 In 1682 Edmond Halley made observations of the position of the bright comet that bears his name. Halley visited Isaac Newton to encourage him to research the orbit, as he did and demonstrated that the orbit the comet was sensibly parabolic.2

Halley concluded that the comet would be seen again about the end of 1758 or the beginning of 1759.2 Some year before, the Spanish Naval Observatory was founded at Cádiz (Spain) in 1753 as an annex to the Academia de Guardiamarinas (Midshipmen Academy) and it was founded by Jorge Juan, in his desire of advancing astronomical observations among the Navy personnel. At that moment, the Director of the Academia de Guardiamarinas was the astronomer Luis Godín.3 Soon, this observatory was known as the Royal Observatory of Cádiz.

Records of Halley’s comet at the Royal Observatory of Cádiz

One of the first observations by the Royal Observatory of Cádiz was de Sun eclipse in the 26th of October or 1753. Perhaps one of the most important communications of the Observatory were the repercussions in Cádiz of the earthquake of Lisbon (Portugal) the 1st of November of 1755. The world of Astronomy was waiting for Halley’s comet since 1758 as it was announced. The previous visit was on 1682. The prestigious Journal des Sҫavans included several papers about the Halley’s comet. Journal des Sҫavans was one of the publications received by Library of the Royal Observatory of Cádiz,4 actually recognised as one of the most important libraries in astronomy all around de world.

The French astronomer Joseph-Nicolas Delisle had met Halley in London in 1724 and discussed the transit of Venus5 was very interested in the comet. He wrote a first paper about the description of the course of Halley’s comet.6 Godin, who studied astronomy with Delisle at the Royal College of Paris, observed the Halley’s comet in April and May of 1759.7 Delisle was waiting for the information obtained by Godin, and so he wrote.8 The reference about Halley’s comet and the Royal Observatory of Cádiz is included in this letter from Delisle, member of the Academia Royale des Sciences, to the editors of Journal des Sҫavans, with a special note about the advantage of the location of the city of Cádiz for to study Halley’s comet.9 “…je l’espère principalement de l’Espagne, ou M.

Godin, que j’ai aussi averti du retour de cette Comète, aura pû l’appercevoir des premiers à Cadix, à cause de la situation avantageuse de cette Ville qui est une des plus méridionales de l’Europe”. In this paper, and as a part of this history, we incorpórate that the information obtained by Godin arrived and Messier, astronomer who was instructed by Delisle, include this reference about Godin and Cádiz in a paper published in 1765.10



Conflicts of interest

The author declares there is no conflict of interest.


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