Talk:Visibility
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It is not "Intensity", It is Luminance
editIn the Derivation part, FB(x) and F(x) are not intensities. They are luminances! And the reason the equations come in that form is due to an assumption: the attenuation coefficients for lights with different wavelengths are the same. — Preceding unsigned comment added by 222.18.127.124 (talk) 13:10, 14 October 2013 (UTC)
Bug report: disambiguation
editSorry for not fixing this myself, don't have time at the moment, but maybe this comment will help: This article doesn't link to uses of the term 'Visibility' in any field except meteorology. There should be some disambiguation, either on top of this page or on a separate page. —Preceding unsigned comment added by 86.59.11.23 (talk) 01:32, 5 August 2008 (UTC)
New Contrast Standard?
editMultiple sources that I've found (e.g. this one) suggest that 5% is a more appropriate contrast threshold making the "modern" value for Koschmieder's equation 2.99/bext. I'm not an expert on this subject and did not feel comfortable changing the page, but it appears that perhaps someone should. — Preceding unsigned comment added by CoryCohen2 (talk • contribs) 02:39, 2 December 2016 (UTC)
Background Intensity Constant?
editWhy is it stated that F(b) is constant? I would think the white background also changes in its intensity as we move away from it. Are the distance from the observer to the object and observer to the background the same? What is the background composed of? — Preceding unsigned comment added by 137.75.200.138 (talk) 00:53, 14 December 2016 (UTC)
Other things can also change, such as the amount of scattered light into the beam depending on the scattering angle. Thus a more accurate treatment of visibility would be found here: https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/met.42 — Preceding unsigned comment added by 137.75.200.138 (talk) 21:52, 20 June 2018 (UTC)
Measurement methods
editInformation on how visibility is measured, especially by automated means might be useful.... http://www.nws.noaa.gov/asos/vsby.htm seems to be a potential public domain source for at least one method.... Other (non-PD) sources: http://www.metoffice.gov.uk/guide/weather/observations-guide/how-we-measure-visibility http://www.wral.com/weather/blogpost/3095296/ (Interesting, the manual methods seems to vary between the US and UK, UK takes lowest value, US seems to take the greatest value for more than 50% of the directions) MoHaG (talk) 09:10, 11 January 2017 (UTC)
Size of objects?
editThis whole article seems to discuss only the visibility of objects of undefined "suitible dimensions". I don't understand how anything so meaninglessly vague could actually be used in real life. Surely, a black mountain is visible from a further distance than a black pebble, but the equations and the official aviation definition appear to ignore object size as a factor. I think this article needs additional, clearer sources and information. 2601:441:4480:53B0:649E:4D07:C305:5E01 (talk) 15:55, 27 October 2018 (UTC)
Mist and haze
editThe practice differs from one country to another but distinction between haze and fog is done by assuming the relative humidity. Most countries in Central/Eastern Europe (Hungary, Slovakia, Croatia, Austria etc.) follows the next: when the visibility is at least 1km and at most 5km, then a) mist should be observed when the relative humidity is at least 80% or b) haze should be observed when relative humidity is less than 80%. In Germany, however, airfields with a significant light aircraft traffic (and AFAIK the military airports as well) has an upper visibility threshold of 8km instead of 5km for mist/fog. (I work in the Hungarian Meteorological Service, Unit of Aviation Meteorology so I'm sure I can find there sources if I will have time, but I don't have them at home and don't want to edit the article without them.) PeterSalavec (talk) 23:03, 16 January 2020 (UTC)
History section
editWhy is there a need for history behind the definition and calculations for visibility? Any information regarding scientists that contributed to the study of visibility can be mentioned briefly in the general information section at the top. Should the history section be deleted? Justanotherinternetguy (talk) 21:28, 20 July 2023 (UTC)