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Perhaps this article could use diagrams illustrating some or all of the named rays.-- Srleffler 06:14, 9 December 2005 (UTC)
I'm concerned about this edit. The editor appears to be trying to clarify or correct the definitions, but the new material is not so clear to me. I'm not sure what he/she means by "starts at the object". Assuming the object is not a point, to define a ray you have to specify where on the object the ray starts. The old text did so (although it also made some assumptions and was not so clear). It is not clear to me that these new changes are correct. -- Srleffler 06:28, 29 November 2007 (UTC)
Expanding on the above, the new definitions given for marginal and chief rays are not in agreement with those in Greivenkamp's book (reference in article), and are uncited. I will revert for now to the definitions that have citation support. I particularly note that the claim that images are formed where the marginal ray crosses the chief ray (as opposed to the optic axis) appears to be wrong. Perhaps we just have conflicting definitions of the same terms, used by different authors. If that is the case, a citation needs to be provided in support of the other definition, and the article needs to be broadened to explain and compare both usages.-- Srleffler 20:44, 2 December 2007 (UTC)
As far as I can tell, only principal rays (= chief rays?) are used in diagrams related to image perspective; including angle of view, entrance pupil, etc whereas diagrams showing how the image is focussed use marginal rays (?) as well. Please could someone explain / elaborate on this ? If I'm on the right lines this should be quite an important "key" to avoiding misinterpretation of ray diagrams. Redbobblehat ( talk) 14:33, 2 September 2008 (UTC)
I came across this definition of a third conjugate ray :
From the diagram on p238, a pair of PRs flank the chief ray through the system - diverging from the same object point and converging to the same image point as the chief ray, but passing through the edges of the aperture instead of the centre. Something similar is depicted (but unnamed) in Fig.2 of van Walree's on Distortion [2] ...?
Google can find no other reference to a "pharoid ray", and "pharoid" (or similar) does not appear in any of the dictionaries I checked. Is this concept - possibly going under a different name - familiar to anyone ? -- Redbobblehat ( talk) 16:57, 14 August 2009 (UTC)
The new entry on parabasal rays doesn't accurately capture what the source is saying. The source is poorly worded, which doesn't help. What distinguishes these rays is not that they are close to the chief ray, but that they are "real" rays instead of "paraxial" ones. In Zemax and other optical design software, rays can be traced in two ways: a paraxial raytrace makes the paraxial approximation and ignores the physical shape of the surfaces, treating them as flat interfaces with a given optical power. This is a crude assumption, but was traditionally used because the raytracing calculation was very fast. It's also the appropriate assumption for analyzing first-order properties of the lens. Alternatively, Zemax can trace the real path of any given ray through the system, taking full account of the shapes of the interfaces and using Snell's law without approximation. On a modern computer there is little reason not to do this, so "real rays" are used for most purposes.
The author presumes that the chief and marginal rays are treated paraxially. (I forget whether this usage is typical in Zemax.) His parabasal rays are real rays traced in the paraxial limit, but without making the paraxial approximation.
Confusingly, the author's "chief rays" originate at the point where the object plane intersects the optical axis, rather than from the edge of the object. I'm not sure if this is a Zemax-specific usage or if it has wider support. What is going on, is the author would consider an optical system to have many "chief rays", one from each point on an object. (In Zemax terminology each field point has its own chief ray.) The (cited) definition used here, on the other hand, considers an optical system to have a single chief ray, defined by the most extreme object point.
I can try to rewrite the new entry, but I'm not sure I can do that without improper synthesis. It would be good to have a better source.-- Srleffler ( talk) 17:30, 17 August 2009 (UTC)
It seems that the term "finite ray" is commonly used to describe rays which are traced without the paraxial approximation : [10], [11], [12], [13]. -- Redbobblehat ( talk) 12:35, 18 August 2009 (UTC)
Warren J. Smith defines trigonometric ray as "A ray the path of which is traced according to Snell’s law (which see) as opposed to a paraxial ray. Also called an exact ray." (Modern optical engineering Fourth Edition 2007, p.731 [14]).-- Redbobblehat ( talk) 17:24, 18 August 2009 (UTC)
I think we need to get rid of the figure and caption that refers to light as "oscillating in amplitude" as it travels. First of all, it doesn't. It oscillates in phase. The electric field oscillates, but when one refers to "amplitude" in optics, it's understood to mean something other than the instantaneous magnitude of the electric field. Second, that figure adds absolutely no information, and is meaningless and confusing. Why does it help one understand ray optics? The wave nature of light doesn't even come into account in ray optics, so why is this even here?
If nobody objects, I'll delete it. Birge ( talk) 22:20, 23 September 2009 (UTC)
I added a link to this question in the section "See also". It is mentioned at the end of the section on boundary value problem of the article Computation of radiowave attenuation in the atmosphere -- Thuytnguyen48 ( talk) 15:08, 18 October 2010 (UTC)
A significant proportion of optical engineers (especially those trained at the University of Rochester) and optical texts refer to marginal rays as a rays and chief rays as b rays. I am tentatively going to plug these names as parenthetical notes in to the main article, unless anyone sees a reason not to. I'll provide a textbook reference when I have one in front of me. Most of them acknowledge a ray and b ray as alternative terms. 128.151.226.73 ( talk) 19:32, 20 October 2010 (UTC)
The first definition in Newton's Optics is the ray. It is a least part of light moving in a line. His definition appeals to me because it is intuitive and practical rather than formal. It seems nice to have this around.
from: http://www.gutenberg.org/files/33504/33504-h/33504-h.htm
DEFIN. I.
By the Rays of Light I understand its least Parts, and those as well Successive in the same Lines, as Contemporary in several Lines. For it is manifest that Light consists of Parts, both Successive and Contemporary; because in the same place you may stop that which comes one moment, and let pass that which comes presently after; and in the same time you may stop it in any one place, and let it pass in any other. For that part of Light which is stopp'd cannot be the same with that which is let pass. The least Light or part of Light, which may be stopp'd alone without the rest of the Light, or propagated alone, or do or suffer any thing alone, which the rest of the Light doth not or suffers not, I call a Ray of Light.
AJim ( talk) 03:40, 14 April 2011 (UTC)
What bothers me about the current definition in the article is that it is narrowly focussed on ray tracing. I think it excludes talking about the polarization of a ray, for instance. I fear that this narrow definition may exclude some historic uses of the word, which may be confusing. Faraday, for instance, famously wrote, "...I have magnetized a ray of light...", and that ray was linearly polarized. AJim ( talk) 04:09, 14 April 2011 (UTC)
I want some advise. I was reading an article on colors and the term "incident light" is mentioned. As a good but not native english language speaker and reader, the word "incident" is unknown to me. So I edited the article, put 2 square brackets around it and am happy the term turns blue. So I hoover over it to see what it means, unfortunately it redirects to "ray". That's not useful. In the article on rays the term isn't mentioned either, only "incident ray" is mentioned with a drawing and I derive from it incident means incoming light. What should we do? Is that just a bummer for non-native english speakers and they just have to look it up in a translator or do we mention it under the redirect code of the incident light article or should it be mentioned in the article on "ray"? Thx -- SvenAERTS ( talk) 10:38, 9 August 2011 (UTC)
Light beam seems to describe the same thing, but artificial. The terms are interchangeable, right?-- عبد المؤمن ( talk) 18:36, 1 March 2014 (UTC)
Out of incident, reflected, and refracted rays, only "angle of incidence" currently has its own article. The article is just a definition of "angle of incidence" and "glancing angle". I think it would be better explained in context, as a part of this overview article on the ray formalism. They're both pretty short, and there's some repetition of content. Main concern is WP:DICT. Forbes72 ( talk) 21:32, 22 March 2016 (UTC)
I'm going to revert some of the wording changes, as they are more complicated, less clear, and not more accurate.
For marginal rays:
is better than
Firstly, images can be formed at more than one location. The marginal rays cross the axis every time an image is formed, not only at the final image plane of the system.
I'm not sure what User:Goodphy was trying to achieve with the rest of this change. The rest of the paragraph is just less clear with the new wording, and may not even be correct. There is no need to extend straight lines along anything. The marginal ray bends when it passes through optical surfaces. Its distance from the axis at a pupil defines the size of the pupil. -- Srleffler ( talk) 22:49, 2 September 2023 (UTC)
Similarly for chief rays:
is better than
There is no need to extend straight lines along anything. The chief ray simply crosses the axis at the locations of the pupils. (The ray's path bends when it passes through optical surfaces.)-- Srleffler ( talk) 23:03, 2 September 2023 (UTC)
This
level-5 vital article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||||||||||
|
It is requested that an optical diagram or diagrams be
included in this article to
improve its quality. Specific illustrations, plots or diagrams can be requested at the
Graphic Lab. For more information, refer to discussion on this page and/or the listing at Wikipedia:Requested images. |
Perhaps this article could use diagrams illustrating some or all of the named rays.-- Srleffler 06:14, 9 December 2005 (UTC)
I'm concerned about this edit. The editor appears to be trying to clarify or correct the definitions, but the new material is not so clear to me. I'm not sure what he/she means by "starts at the object". Assuming the object is not a point, to define a ray you have to specify where on the object the ray starts. The old text did so (although it also made some assumptions and was not so clear). It is not clear to me that these new changes are correct. -- Srleffler 06:28, 29 November 2007 (UTC)
Expanding on the above, the new definitions given for marginal and chief rays are not in agreement with those in Greivenkamp's book (reference in article), and are uncited. I will revert for now to the definitions that have citation support. I particularly note that the claim that images are formed where the marginal ray crosses the chief ray (as opposed to the optic axis) appears to be wrong. Perhaps we just have conflicting definitions of the same terms, used by different authors. If that is the case, a citation needs to be provided in support of the other definition, and the article needs to be broadened to explain and compare both usages.-- Srleffler 20:44, 2 December 2007 (UTC)
As far as I can tell, only principal rays (= chief rays?) are used in diagrams related to image perspective; including angle of view, entrance pupil, etc whereas diagrams showing how the image is focussed use marginal rays (?) as well. Please could someone explain / elaborate on this ? If I'm on the right lines this should be quite an important "key" to avoiding misinterpretation of ray diagrams. Redbobblehat ( talk) 14:33, 2 September 2008 (UTC)
I came across this definition of a third conjugate ray :
From the diagram on p238, a pair of PRs flank the chief ray through the system - diverging from the same object point and converging to the same image point as the chief ray, but passing through the edges of the aperture instead of the centre. Something similar is depicted (but unnamed) in Fig.2 of van Walree's on Distortion [2] ...?
Google can find no other reference to a "pharoid ray", and "pharoid" (or similar) does not appear in any of the dictionaries I checked. Is this concept - possibly going under a different name - familiar to anyone ? -- Redbobblehat ( talk) 16:57, 14 August 2009 (UTC)
The new entry on parabasal rays doesn't accurately capture what the source is saying. The source is poorly worded, which doesn't help. What distinguishes these rays is not that they are close to the chief ray, but that they are "real" rays instead of "paraxial" ones. In Zemax and other optical design software, rays can be traced in two ways: a paraxial raytrace makes the paraxial approximation and ignores the physical shape of the surfaces, treating them as flat interfaces with a given optical power. This is a crude assumption, but was traditionally used because the raytracing calculation was very fast. It's also the appropriate assumption for analyzing first-order properties of the lens. Alternatively, Zemax can trace the real path of any given ray through the system, taking full account of the shapes of the interfaces and using Snell's law without approximation. On a modern computer there is little reason not to do this, so "real rays" are used for most purposes.
The author presumes that the chief and marginal rays are treated paraxially. (I forget whether this usage is typical in Zemax.) His parabasal rays are real rays traced in the paraxial limit, but without making the paraxial approximation.
Confusingly, the author's "chief rays" originate at the point where the object plane intersects the optical axis, rather than from the edge of the object. I'm not sure if this is a Zemax-specific usage or if it has wider support. What is going on, is the author would consider an optical system to have many "chief rays", one from each point on an object. (In Zemax terminology each field point has its own chief ray.) The (cited) definition used here, on the other hand, considers an optical system to have a single chief ray, defined by the most extreme object point.
I can try to rewrite the new entry, but I'm not sure I can do that without improper synthesis. It would be good to have a better source.-- Srleffler ( talk) 17:30, 17 August 2009 (UTC)
It seems that the term "finite ray" is commonly used to describe rays which are traced without the paraxial approximation : [10], [11], [12], [13]. -- Redbobblehat ( talk) 12:35, 18 August 2009 (UTC)
Warren J. Smith defines trigonometric ray as "A ray the path of which is traced according to Snell’s law (which see) as opposed to a paraxial ray. Also called an exact ray." (Modern optical engineering Fourth Edition 2007, p.731 [14]).-- Redbobblehat ( talk) 17:24, 18 August 2009 (UTC)
I think we need to get rid of the figure and caption that refers to light as "oscillating in amplitude" as it travels. First of all, it doesn't. It oscillates in phase. The electric field oscillates, but when one refers to "amplitude" in optics, it's understood to mean something other than the instantaneous magnitude of the electric field. Second, that figure adds absolutely no information, and is meaningless and confusing. Why does it help one understand ray optics? The wave nature of light doesn't even come into account in ray optics, so why is this even here?
If nobody objects, I'll delete it. Birge ( talk) 22:20, 23 September 2009 (UTC)
I added a link to this question in the section "See also". It is mentioned at the end of the section on boundary value problem of the article Computation of radiowave attenuation in the atmosphere -- Thuytnguyen48 ( talk) 15:08, 18 October 2010 (UTC)
A significant proportion of optical engineers (especially those trained at the University of Rochester) and optical texts refer to marginal rays as a rays and chief rays as b rays. I am tentatively going to plug these names as parenthetical notes in to the main article, unless anyone sees a reason not to. I'll provide a textbook reference when I have one in front of me. Most of them acknowledge a ray and b ray as alternative terms. 128.151.226.73 ( talk) 19:32, 20 October 2010 (UTC)
The first definition in Newton's Optics is the ray. It is a least part of light moving in a line. His definition appeals to me because it is intuitive and practical rather than formal. It seems nice to have this around.
from: http://www.gutenberg.org/files/33504/33504-h/33504-h.htm
DEFIN. I.
By the Rays of Light I understand its least Parts, and those as well Successive in the same Lines, as Contemporary in several Lines. For it is manifest that Light consists of Parts, both Successive and Contemporary; because in the same place you may stop that which comes one moment, and let pass that which comes presently after; and in the same time you may stop it in any one place, and let it pass in any other. For that part of Light which is stopp'd cannot be the same with that which is let pass. The least Light or part of Light, which may be stopp'd alone without the rest of the Light, or propagated alone, or do or suffer any thing alone, which the rest of the Light doth not or suffers not, I call a Ray of Light.
AJim ( talk) 03:40, 14 April 2011 (UTC)
What bothers me about the current definition in the article is that it is narrowly focussed on ray tracing. I think it excludes talking about the polarization of a ray, for instance. I fear that this narrow definition may exclude some historic uses of the word, which may be confusing. Faraday, for instance, famously wrote, "...I have magnetized a ray of light...", and that ray was linearly polarized. AJim ( talk) 04:09, 14 April 2011 (UTC)
I want some advise. I was reading an article on colors and the term "incident light" is mentioned. As a good but not native english language speaker and reader, the word "incident" is unknown to me. So I edited the article, put 2 square brackets around it and am happy the term turns blue. So I hoover over it to see what it means, unfortunately it redirects to "ray". That's not useful. In the article on rays the term isn't mentioned either, only "incident ray" is mentioned with a drawing and I derive from it incident means incoming light. What should we do? Is that just a bummer for non-native english speakers and they just have to look it up in a translator or do we mention it under the redirect code of the incident light article or should it be mentioned in the article on "ray"? Thx -- SvenAERTS ( talk) 10:38, 9 August 2011 (UTC)
Light beam seems to describe the same thing, but artificial. The terms are interchangeable, right?-- عبد المؤمن ( talk) 18:36, 1 March 2014 (UTC)
Out of incident, reflected, and refracted rays, only "angle of incidence" currently has its own article. The article is just a definition of "angle of incidence" and "glancing angle". I think it would be better explained in context, as a part of this overview article on the ray formalism. They're both pretty short, and there's some repetition of content. Main concern is WP:DICT. Forbes72 ( talk) 21:32, 22 March 2016 (UTC)
I'm going to revert some of the wording changes, as they are more complicated, less clear, and not more accurate.
For marginal rays:
is better than
Firstly, images can be formed at more than one location. The marginal rays cross the axis every time an image is formed, not only at the final image plane of the system.
I'm not sure what User:Goodphy was trying to achieve with the rest of this change. The rest of the paragraph is just less clear with the new wording, and may not even be correct. There is no need to extend straight lines along anything. The marginal ray bends when it passes through optical surfaces. Its distance from the axis at a pupil defines the size of the pupil. -- Srleffler ( talk) 22:49, 2 September 2023 (UTC)
Similarly for chief rays:
is better than
There is no need to extend straight lines along anything. The chief ray simply crosses the axis at the locations of the pupils. (The ray's path bends when it passes through optical surfaces.)-- Srleffler ( talk) 23:03, 2 September 2023 (UTC)