Talk:Fraunhofer lines

2006

It would be useful to discuss the meaning of the X and Y axis in the graphic. I assume the Y axis represents frequency (due to the use of colors), but it is unclear what the X axis represents.

I believe that the X axis represents the elements (from Hydrogen to ?). MichaelGoldshteyn 17:43, 3 October 2006 (UTC)

What are you talking about? Its all frequency. its just a looped continuous spectrum. --Deglr6328 10:55, 19 October 2006 (UTC)

G' or f?

In the "Naming" section the line betreen G end e is called G', but in the top image it's marked as f. Also in this page it's called f (visible hydrogen spectrum lines correspond to lines C, F, f and h, at the bottom of the page), while wiki page currently says they correspond to C, F, G' and h. Can someone explain what's begind this? Should it be called G'/f to avoid confusion or maybe only f? — Preceding unsigned comment added by 93.106.55.102 (talk) 11:15, 3 July 2014 (UTC)

G band

In some sources it can be found, that G band correponds to CH ( or ), not only to Fe and Ca. Orionus 15:56, 25 July 2007 (UTC)

O₂ is a compound

In the table, O₂ is listed even though the element is O. Is there a reason for this? --196.210.102.113 (talk) 20:45, 16 January 2008 (UTC)

The A, B and a lines are so-called "telluric" lines which arise from absorption (in this case by molecular oxygen, O₂) in the Earth's atmosphere . Spacepotato (talk) 23:09, 16 January 2008 (UTC)

Adding image with spectrum as you can see it visually with a prism

I think it would be helpful to add a picture of the solar spectrum from red to violet as you would see it with a prism. Makes the Fraunhofer lines more concrete than than a graph with intensity against wavelength.Arjen Dijksman (talk) 14:40, 6 March 2009 (UTC)

Looks like someone has done it with (Fraunhofer lines.svg) - Rod57 (talk) 01:06, 26 February 2015 (UTC)

Ah the text is messed up in this section. Fraunhofer lines don't appear visually. Need to state that this what you see when passing the light through a dispersive prism onto a dark screen... please don't look at the sun! 69.198.171.61 (talk) 19:46, 20 March 2023 (UTC)

More precise information

It is written in the aricle, that Frauenhofer discovered 570 absorption lines. Were they all within the visible part of the solar spectrum? —Preceding unsigned comment added by 203.100.215.57 (talk) 03:53, 7 November 2009 (UTC)

How wide and deep are the lines ?

Could the table be extended with line width and depth (eg % extinction) ? - Rod57 (talk) 01:03, 26 February 2015 (UTC)

Wavelengths in vacuum or air?

Presumably the wavelengths given here are measured in "standard air," not vacuum. The article really needs to say that! And even better would be to also provide information (or a link to information) about converting to vacuum wavelengths. — Preceding unsigned comment added by Srw137 (talk • contribs) 23:38, 1 April 2020 (UTC)

Yes good point! It is also extremely important to mention the source here. No clue where this list came from. I checked the NIST Atomic lines database, and at least Na D1/2 seem to have their air value. --2001:982:205C:1:CBB5:BCD0:96B3:D2A6 (talk) 15:40, 29 December 2021 (UTC)

Also, I would like to add that by looking at the telluric lines in my high resolution Mercator Hermes spectra, I checked the locations of the O2 lines at 822.696, 759.370, 686.719, 627.661. All of them were accurate to within 0.5km/s, except for the 686.719 line which was clearly off by about 2km/s. It seems to have a value closer to 6867.24. I Googled around and did find values of 686.719nm, but they never had good supporting references. There may be pressure effects going on here which could explain the difference.

We badly need to cross-check this data with a molecular lines database. I don't have access to that, so I am relying on Wikipedia instead... --2001:982:205C:1:CBB5:BCD0:96B3:D2A6 (talk) 16:33, 29 December 2021 (UTC)

Cosine

The phrase "cosine corrector" has no meaning. It is worthless without a link to a Wikipedia Page but none such exists. I have a Ph.D. in Biophysics from Harvard, and have no idea what "cosine corrector" means. I do not understand why this one technical detail of the instrument is mentioned, but no other technical detail is. I am removing it, someone who knows needs to explain it, in the article, before returning it to this article. Nick Beeson (talk) 13:41, 2 April 2025 (UTC)

Featured picture scheduled for POTD

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The Fraunhofer lines are a set of spectral absorption lines. They are dark absorption lines, seen in the optical spectrum of the Sun, and are formed when atoms in the solar atmosphere absorb light being emitted by the solar photosphere. The lines are named after the German physicist Joseph von Fraunhofer, who observed them in 1814. This image shows the solar spectral irradiance measured with a calibrated optical spectrometer, as viewed on a sunny day in Switzerland in 2022. Some of the characteristic Fraunhofer lines and their corresponding elements are indicated for the extended visible spectrum – the highlighted area of the graph.

Graph credit: Cyamahat

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