Talk:Sunlight

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[edit] Alternative images

Beach Towel (occupied).jpg

Enjoying the sunlight

[edit] 93 lumens of illumination per watt

"Direct sunlight gives about 93 lumens of illumination per watt of electromagnetic power, including infrared, visible, and ultra-violet. This compares with the best fluorescent lights."

This is a very confused/confusing paragraph, perhaps accreted from various contributors. If the first sentence is true, it is a very technical matter, having to do with the spectrum of the light and the way the human eye responds. (This is *not* a measure of the sun's efficiency at turning energy into light.) (See Photometry (optics) and Luminosity function.) The second sentence would appear to reference the production of light from electricity, technically a quite different -- there are no comparable numbers to compare here! I am going to remove the second sentence.-69.87.203.17 20:22, 27 May 2007 (UTC)

[edit] Spectrum of blue sky

"Spectrum of blue sky clearly showing solar Fraunhofer lines and atmospheric water absorption band."

This is a terrible graphic [1] to include in a Sunlight article. It is either very wrong, or just very misleading in this context. It shows almost nothing past visible, perhaps because of sensor limitations. Half of sunlight is IR, and there is some UV down to 300 nm. Actually, the comments with the image acknowledge how poor this data set is -- I'll try to remove it. There are great full-spectrum plots at Solar radiation.-69.87.203.17 20:36, 27 May 2007 (UTC)

[edit] Article needs rewriting

Seriously. First sentence, "Sunlight is bright."? There are other moderately funny/weird things in the article further on. Mild vandalism, perhaps? I'd put a rewrite tag on it but I don't know how.GreenSprite 09:12, 7 September 2007 (UTC)

[edit] This sentence is almost insultingly obvious.

  "  This is usually during the hours known as day. "

And what brilliant astronomer discoveered this curious little theory? —Preceding unsigned comment added by 164.92.175.76 (talk) 16:06, 25 February 2008 (UTC)

[edit] "Calculation" paragraph

Greetings, I am reading the "Calculation" paragraph, and wondering if the formula is valid at "noon", and / or at the moment of the day when a meridian is facing the sun perpendicularly? Essentially I think the paragraph should mention at which time of the day is the formula valid.

I am also wondering whether "Eext" is the illuminance on "top" of the atmosphere, or on the Earth as if there was no atmosphere? Lastly, I wish a few possible values were given for "c" and "m" (and "Edn"), and that "e" was clarified as being Euler's constant, if that's indeed what it is. —Preceding unsigned comment added by Jfclemay (talk • contribs) 21:31, 4 May 2008 (UTC)

Correction, I just realized that the formula doesn't consider latitude or longitude, sorry. In which case I am wondering if the lux value "Eext" is the quantity of lumens reaching the Earth, divided by half the area of the Earth's sphere? —Preceding unsigned comment added by 82.45.130.213 (talk) 22:22, 4 May 2008 (UTC)