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In these changes, @ PostaDiDonna: replaced the illustration File:Eratosthenes_measure_of_Earth_circumference.svg with File:Eratostene--Calcolo_Raggio_Terrestre.jpg.
Though I agree with the new caption noting that Syene and Alexandria are not on the same meridian, I believe that the original image is more accurate as the angle is to scale and being an SVG, it can be easily translated.
May I get a second opinion on this?
Thanks,
cmɢʟee⎆
τaʟκ 22:26, 26 August 2021 (UTC)
The article currently states [Eratosthenes] estimated that the meridian has a length of 252,000 stadia (39,060-40,320 km), with an error on the real value between −2.4% and +0.8% (assuming a value for the stadion between 155 and 160 metres) but I am fairly certain the upper limit here is incorrect (as stated in this source which claims it is 29,000 miles or around 46,000km). However, I am hesitant to change the article due to a source being referenced for the values currently used. I would refer to the source itself but I am unable to access the source (as it is a book). SailorFox ( talk) 09:03, 28 November 2021 (UTC)
The estimation of one stade equal to 155-160 meter is misleading. It should be changed to 185 meter. The cited source (Donald Engels (1985). The Length of Eratosthenes' Stade. American Journal of Philology 106 (3): 298–311. doi:10.2307/295030) clearly states that one stade was 185 meter and not 155-160 meter, which gives an estimate of 46,000km to earth's diameter. The estimation of one stade being equal to 185 meter is the one accepted by most scholars (see, e.g., page 20 in Ptolemaais, Klaudios, J. Lennart Berggren, and Alexander Jones. Ptolemy's Geography: an annotated translation of the theoretical chapters. Princeton University Press, 2000.)
Hy I want to put some information about geometry 103.150.209.69 ( talk) 17:34, 1 June 2022 (UTC)
So we get another one of these fabricated portraits of the 17th/18th century, without explanation and without sourcing (even in the commons file). Good work! 2A02:AA1:1020:A09C:59CD:2C68:3B5E:177A ( talk) 16:58, 25 July 2022 (UTC)
This section:
The simplified method works by considering two cities along the same meridian and measuring both the distance between them and the difference in angles of the shadows cast by the sun on a vertical rod (a gnomon) in each city at noon on the summer solstice.
I don't think there is any requirement for the two cities to be at the same meridian if each measurement is taken at Local Apparent Noon (LAN). At LAN in Syene at summer solstice there would be no shadow and at Alexandria On the same day LAN could be determined as the time the shadow of a gnomon was at it shortest. CaptCarlsen ( talk) 16:31, 17 February 2024 (UTC)
This
level-4 vital article is rated B-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
This page has archives. Sections older than 365 days may be automatically archived by Lowercase sigmabot III when more than 5 sections are present. |
In these changes, @ PostaDiDonna: replaced the illustration File:Eratosthenes_measure_of_Earth_circumference.svg with File:Eratostene--Calcolo_Raggio_Terrestre.jpg.
Though I agree with the new caption noting that Syene and Alexandria are not on the same meridian, I believe that the original image is more accurate as the angle is to scale and being an SVG, it can be easily translated.
May I get a second opinion on this?
Thanks,
cmɢʟee⎆
τaʟκ 22:26, 26 August 2021 (UTC)
The article currently states [Eratosthenes] estimated that the meridian has a length of 252,000 stadia (39,060-40,320 km), with an error on the real value between −2.4% and +0.8% (assuming a value for the stadion between 155 and 160 metres) but I am fairly certain the upper limit here is incorrect (as stated in this source which claims it is 29,000 miles or around 46,000km). However, I am hesitant to change the article due to a source being referenced for the values currently used. I would refer to the source itself but I am unable to access the source (as it is a book). SailorFox ( talk) 09:03, 28 November 2021 (UTC)
The estimation of one stade equal to 155-160 meter is misleading. It should be changed to 185 meter. The cited source (Donald Engels (1985). The Length of Eratosthenes' Stade. American Journal of Philology 106 (3): 298–311. doi:10.2307/295030) clearly states that one stade was 185 meter and not 155-160 meter, which gives an estimate of 46,000km to earth's diameter. The estimation of one stade being equal to 185 meter is the one accepted by most scholars (see, e.g., page 20 in Ptolemaais, Klaudios, J. Lennart Berggren, and Alexander Jones. Ptolemy's Geography: an annotated translation of the theoretical chapters. Princeton University Press, 2000.)
Hy I want to put some information about geometry 103.150.209.69 ( talk) 17:34, 1 June 2022 (UTC)
So we get another one of these fabricated portraits of the 17th/18th century, without explanation and without sourcing (even in the commons file). Good work! 2A02:AA1:1020:A09C:59CD:2C68:3B5E:177A ( talk) 16:58, 25 July 2022 (UTC)
This section:
The simplified method works by considering two cities along the same meridian and measuring both the distance between them and the difference in angles of the shadows cast by the sun on a vertical rod (a gnomon) in each city at noon on the summer solstice.
I don't think there is any requirement for the two cities to be at the same meridian if each measurement is taken at Local Apparent Noon (LAN). At LAN in Syene at summer solstice there would be no shadow and at Alexandria On the same day LAN could be determined as the time the shadow of a gnomon was at it shortest. CaptCarlsen ( talk) 16:31, 17 February 2024 (UTC)