Talk:Pierre Janssen

Photograph

Why is a photograph taken by Janssen of a dirigible needed in this article? It's an interesting old picture, but does it tell the reader much about Janssen? -- Astrochemist 12:37, 12 May 2007 (UTC)

10 years later, I can only agree. Jan olieslagers (talk) 13:13, 18 August 2017 (UTC)

Discovery of helium: 8th or 18th of August ?

I notice that despite Janssen's priority, Encyclopaedia Britannica 1911 wants to give credit for the discovery of helium to Norman Lockyer, an Englishman by coincidence. *cough* Preumably that's why the 1911 text made no mention of helium in Janssen's entry, even though it covered the 1868 Indian eclipse expidition fairly well. -- John Owens (talk) 2005 July 7 03:48 (UTC)

When was helium first discovered ? Helium#Discoveries says 1868 August 18. Pierre Jules César Janssen says August 8. Other descriptions of the events seem to be the same on the two wikipages, but one of them is wrong. Can someone in the know fix this, please ? Thanks. -- PFHLai 06:12, 2005 August 17 (UTC)

All we need is the exact date of the solar eclipse in India of that year. I found this page, that seems to indicate that August 18 is the correct date. Awolf002 13:39, 17 August 2005 (UTC)

Great ! Thank you ! Tomorrow is the anniversary, eh ! I'll fix the article accordingly. -- PFHLai 17:00, 2005 August 17 (UTC)

I think we neeed much more. More than one source says that there is no evidence for that Janssen discovered helium spectral line ("D3 line") (see e.g. [1], the other is a Springer link pdf and I can't link it here). For example, he allegedly didn't say a word about it in his report to the French Academy (1968). Encyclopaedia Britannica also don't mention it he would be a discoverer of helium(-line) [2]. Is there any primary source that gives an obvious evidence Janssen discovered this spectrum line at all? Gubbubu (talk) 10:23, 17 January 2010 (UTC)

Well, there's Janssen's letter to the French Academy of Sciences, dated 19 September, in which he says "The analysis of their light [of solar prominences] immediately showed me that they were formed by an immense colum of incandescent gas, principally composed of hydrogen gas." [emphasis added] and also "these results seem to me to lead to the true knowledge of the composition of the solar spectrum" [original French: ces résultats me paraissent devoir conduire à la connaissance de la véritable constitution du spectre solaire]. See also this long obituary of Norman Lockyer, which amply indicates that Lockyer did not dispute the coincidental discovery. I can't read the articles that Gubbubu cites, but this would not be the first time that nonsense has been written in place of proper history of science. Physchim62 (talk) 03:09, 18 March 2010 (UTC)

Could the date issue be due to use of different calenders? Like the Russian October revolution that actually happened in November? Jan olieslagers (talk) 19:47, 20 August 2017 (UTC)

Simpsons Reference

If people want to put it in, let them, and leave it there. It doesn't matter if it's considered 'trivial'. —Preceding unsigned comment added by 124.171.199.225 (talk) 12:56, 28 October 2007 (UTC)

Some additions

Today I split the Janssen article into sections, added some new pictures, and put in some additional references. Can someone write more about Janssen's early life or on his contributions to solar photography? - Astrochemist 17:57, 18 August 2007 (UTC)

WikiProject class rating

This article was automatically assessed because at least one article was rated and this bot brought all the other ratings up to at least that level. BetacommandBot 07:49, 27 August 2007 (UTC)

Broken link

The link in : Janssen statue at Meudon (color photopgraph) seems to be broken —Preceding unsigned comment added by Jsryork (talk • contribs) 13:05, 18 August 2008 (UTC)

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Helium or no Helium?

The lede paragraph states: "but there is no justification for the conclusion that he deserves credit for the co-discovery of the element helium.", and then the article goes on to a section titled "Discovery of Helium". I think the section is suggesting that Janssen did not actually identify or contribute to Lockyer discovering Helium, but I'm not 100%. If that is the case, the section header should be changed to something like "Solar spectroscopy" or something. TheHYPO (talk) 16:09, 26 July 2024 (UTC)