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Analysis of the Tamil Parallax Procedures in Le Gentil's Report of 1776

Gislén, Lars LU (2023) In Journal of Astronomical History and Heritage 26(2). p.391-399
Abstract
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 procedures are compared with the parallax procedures in Sūryasiddhānta and give similar results. It is found that there seems to be little theoretical background to the Tamil procedures, although they work rather well in practice. There are parallels with parallax procedures in Southeast Asian... (More)
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 procedures are compared with the parallax procedures in Sūryasiddhānta and give similar results. It is found that there seems to be little theoretical background to the Tamil procedures, although they work rather well in practice. There are parallels with parallax procedures in Southeast Asian traditional astronomy. The Tamil calculations of the circumstances of the lunar eclipse 13 December 1769 have earlier been analyzed by Otto Neugebauer in a paper in Isis. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Astronomical History and Heritage
volume
26
issue
2
pages
9 pages
publisher
National Astronomical Research Institute of Thailand
external identifiers
  • scopus:85172324141
ISSN
1440-2807
DOI
10.3724/SP.J.1440-2807.2023.06.33
language
English
LU publication?
yes
id
7d2d2795-11f8-41ce-aebe-3ed271471e15
date added to LUP
2023-10-05 10:12:41
date last changed
2023-10-09 10:18:28
@article{7d2d2795-11f8-41ce-aebe-3ed271471e15,
  abstract     = {{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 procedures are compared with the parallax procedures in Sūryasiddhānta and give similar results. It is found that there seems to be little theoretical background to the Tamil procedures, although they work rather well in practice. There are parallels with parallax procedures in Southeast Asian traditional astronomy. The Tamil calculations of the circumstances of the lunar eclipse 13 December 1769 have earlier been analyzed by Otto Neugebauer in a paper in Isis.}},
  author       = {{Gislén, Lars}},
  issn         = {{1440-2807}},
  language     = {{eng}},
  number       = {{2}},
  pages        = {{391--399}},
  publisher    = {{National Astronomical Research Institute of Thailand}},
  series       = {{Journal of Astronomical History and Heritage}},
  title        = {{Analysis of the Tamil Parallax Procedures in Le Gentil's Report of 1776}},
  url          = {{https://lup.lub.lu.se/search/files/160339181/CF010ABDF34B4415A7A566F41E050E20.pdf}},
  doi          = {{10.3724/SP.J.1440-2807.2023.06.33}},
  volume       = {{26}},
  year         = {{2023}},
}