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Topic: Aberration of light

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In the News (Fri 18 Jan 19)

  Aberration - LoveToKnow 1911
Aberration Of Light This astronomical phenomenon may be defined as an apparent motion of the heavenly bodies; the stars describing annually orbits more or less elliptical, according to the latitude of the star; consequently at any moment the star appears to be displaced from its true position.
The discovery of the aberration of light in 1725, due to James Bradley, is one of the most important in the whole domain of astronomy.
A re-examination of his previously considered hypotheses as to the cause of these phenomena was fruitless; the true theory was ultimately discovered by a pure accident, comparable in simplicity and importance with the association of a falling apple with the discovery of the principle of universal gravitation.
www.1911encyclopedia.org /Aberration   (2162 words)

 Olympus Microscopy Resource Center: Physics of Light and Color - Common Optical Defects in Lens Systems (Aberrations)
Red light is not refracted at the same angle as green or blue light so the focal point on the optical axis of the lens is farther away from the lens for red light.
Spherical aberrations are very important in terms of the resolution of a lens because they affect the coincident imaging of points along the optical axis and degrade the performance of the lens, which will seriously affect specimen sharpness and clarity.
The aberration is named for its strong resemblance to the shape of a comet tail, and is manifested by a streak of light that appears to emanate from a focused spot at the periphery of the viewfield.
www.olympusmicro.com /primer/lightandcolor/opticalaberrations.html   (2144 words)

 Speed of light   (Site not responding. Last check: 2007-09-11)
At present the speed of light is definition not a measurement as the metre is defined in terms of the of light and not vice versa.
Since the speed of light in vacuum constant it is convenient to measure both and distance in terms of c \ Both the SI unit of length and unit of time have been defined in of wavelengths and cycles of light.
On the basis of his observations estimated that it would take light 22 to cross the diameter of the orbit the Earth (that is twice the astronomical unit); the modern estimate is closer to minutes and 40 seconds.
www.freeglossary.com /Speed_of_light   (2495 words)

 Classical light
In the 1660s Gassendi had put forward the particle theory, suggesting that light was composed of a stream of tiny particles, while Descartes suggested that space was filled with 'plenum' which transmitted pressure from a light source onto the eye.
It discussed the theory of light and colour and dealt with investigations of the colours of thin sheets, 'Newton's rings', and the diffraction of light.
The light which passed through the wheel was sent on a journey of 17.3 kilometres before being reflected back to interfere with light which had passed through the partially reflecting mirror.
www-groups.dcs.st-and.ac.uk /~history/HistTopics/Light_1.html   (4489 words)

 PhysOrgForum Science, Physics and Technology Discussion Forums -> Aberration of light.
Aberration of light is based on the fact that a photon travels in a straight line in space-time (space-time may be curved but the photon doesn't notice).
It was not used to measure "aberration of light" due to the velocity of the Earth.
The aberration of light measured by astronomers is 20.5 arc-seconds.
forum.physorg.com /index.php?showtopic=6302   (1281 words)

 Faster than the Speed of Light?
This is because the speed of light is simply a measure of two properties of the medium of space, or the vacuum, permeability and permittivity.
In fact, aberration data became one of the early methods for measuring the speed of light.
Light from the sun requires 8.3 minutes to travel from the sun to the earth during which time the sun and the earth have moved as much as 20 arc seconds with respect to each other.
www.ldolphin.org /gspeed.html   (1082 words)

 Stellar Aberration
The aberration of starlight was discovered in 1727 by the astronomer James Bradley based on an observed seasonal displacement in the apparent positions of stars, a displacement that was greatest for stars in the direction perpendicular to the orbital plane of the Earth.
However, if light consists of ballistic corpuscles their speeds ought to depend on the relative motion between the source and observer, and these differences in speed ought to be detectable, whereas no such differences were found.
Assuming light always propagates at the fixed speed c relative to the ether, and assuming the Earth is moving at a speed v relative to the ether, we could argue that the transverse speed of light inside our telescope is c+v in one direction and c-v in the other.
www.mathpages.com /rr/s2-05/2-05.htm   (4128 words)

 How to measure Speed of Light.
In 1728 James Bradley, an English physicist, estimated the speed of light in vacuum to be around 301,000 km/s.
Stellar aberration is approximately the ratio of the speed that the earth orbits the sun to the speed of light.
However the velocity of light varies with the intensity of the gravitational field, that is, this is not the speed of light inside gravitational fields.
www.speed-light.info /measure   (798 words)

 Olympus Microscopy Resource Center: Anatomy of the Microscope - Optical Aberrations
Spherical Aberration from Coverslip Thickness Variations - For microscope objectives having high numerical apertures, the optical properties and thickness of the medium lying between the front lens element and the specimen critically affect the calculations necessary to satisfy the aplanatic and sine conditions and otherwise to correct for image aberrations.
When these aberrations occur, the image of a point is focused at sequentially differing heights producing a series of asymmetrical spot shapes of increasing size that result in a comet-like (hence, the term coma) shape to the Airy pattern.
When the aperture function of an objective is non-uniform, or in the case of spherical aberration, the wavefront leaving the lens is no longer spherical with a center positioned at the point of focus in the image plane.
www.olympusmicro.com /primer/anatomy/aberrationhome.html   (1287 words)

 Nikon MicroscopyU: Introduction to Confocal Microscopy: Aberrations and Objectives for Confocal Microscopy
For these objectives, spherical aberration is minimized only when the entire light path has the refractive index of immersion oil (which is the same as that of glass) and accumulates with distance into a medium with a different refractive index.
Figure 4 shows the effects of spherical aberration in confocal microscopy, where the oil immersion 100x plan apochromat objective was used to collect an image of cells labeled with F-Tf and mounted at a depth of either 0 micrometers (the surface of the coverslip) (Figure 4(a)) or 35 micrometers into an aqueous medium (Figure 4(b)).
Since the correction for spherical aberration depends on the length of the optical path through the coverslip, it is adjustable by a collar that is set according to the thickness of the coverslip.
www.microscopyu.com /articles/confocal/confocalaberrations.html   (3555 words)

 Anti Relativity : Stellar Aberration Contradicts Relativity
Stellar aberration is one of the most well known problems with relativity but as usual, the least understood.
Stellar aberration is the effect well known by astronomers to cause stars to shift up to 20.5 arc seconds in their location in the sky.
The light is merely transferred into the entrained "bubble" around the earth which then faithfully carries the modified angle of incedence directly to the observer.
www.anti-relativity.com /stellaraberration.htm   (780 words)

 Stellar Aberration and Einstein's Relativity   (Site not responding. Last check: 2007-09-11)
Stellar aberration is explained by the relative motion between a star and an observer on earth.
It is shown that the description of stellar aberration, in terms of relative transverse velocity between the star and an observer on earth should be corrected, because it is an erroneous interpretation of Einstein's relativity.
One must conclude that it was an error to claim that the aberration of light is caused by the relative transverse velocity between the star and the Earth.
www.newtonphysics.on.ca /Aberration/Aberration.html   (2975 words)

 C-ship: The Aberration of Light
In classical physics, the aberration of light is precisely like the aberration of rain we've just experienced; the only difference is that light travels considerably faster than rain, about 18 million times faster, as a matter of fact.
At a quarter of the speed of light, Newton is still firmly in charge; aberration is behaving linearly, and the contribution of special relativity is less than a quarter of a degree of the total aberration of more than 11°.
Three quarters of the speed of light: relativity now accounts for a substantial fraction of the total aberration, which is already approaching the 45° classical physics predicts we'd measure at the speed of light.
www.fourmilab.ch /cship/aberration.html   (1881 words)

 Nikon MicroscopyU: Interactive Java Tutorials - Chromatic Aberration
Chromatic aberrations are wavelength-dependent artifacts that occur because the refractive index of every optical glass formulation varies with wavelength.
Blue light is refracted to the greatest extent followed by green and red light, a phenomenon commonly referred to as dispersion.
Lateral chromatic aberration is greater for objectives of short focal length and can range from 1.1 to 1.9 percent of the radial distance from the optic axis.
www.microscopyu.com /tutorials/java/aberrations/chromatic/index.html   (1967 words)

 James Bradley Summary
Greatly puzzled by the result, he at last realized that it was due to the finite velocity of light, owing to the velocity of the earth as it moved in an ellipse, which created an aberration of light.
It was not until 1728 that the explanation became evident to him; the shift was due to the speed of light and the velocity of the Earth.
The amount of angling (the amount of the "aberration of light") allowed Bradley to determine the ratio between the speed of light and the velocity of the Earth.
www.bookrags.com /James_Bradley   (1530 words)

 Aberration of light
Such interpretation about the speed of light is possible assuming that a light source emits simultaneously many "lights" of different speeds relative to the emitter but only that of speed c relative to the physical detector is able to release energy.
Eq[8-2] is different from the classical expression of the aberration that assumes an aether associated with S and therefore a light speed c in S but not in S'.
Note: The calculations of this section have been made assuming that the pertinent radiation flows (lights) that will be detected maintain during all its journey a constant speed when that speed is measured relative to a non accelerated frame using normal clocks.
personales.ya.com /carlosla/model/EVA8/Eva8.htm   (1290 words)

 Telescopes, Binoculars, Spotting Scopes, Microscopes, Astronomical Accessories - Best Quality and Low Price
Aberrations, if they occur, are physical optical errors caused by faulty optical design or manufacturing.
Chromatic Aberration is the failure of a lens to bring light of all colors to a common focus.
Astigmatism causes the image of a point light source to appear as an ellipse with the long axis of the ellipse shifting by 90° on opposite sides of the focal plane.
www.scopecity.com /OpticalAberrations.cfm   (525 words)

The effect of stellar aberration seems to be one of the simplest phenomena in astronomical observations.
Aberration can also be derived from relativistic composition law of velocities which when applied in moving frame of source, using inverse Lorentz Transformations, predicts an aberration effect produced by the motion of the source in rest frame as discussed below.
This lack of observational confirmation of active aberration was interpreted as an error in the theory of relativity and as a hint that the latter had to be revised accordingly [2-5].
www.rajandogra.freeservers.com   (2794 words)

He maintained that the aberration of the light of stars was due to the time that light took to traverse space.
But light in space is diffuse, and wherever the Earth may happen to be in its orbit, the light of the stars will always be there ahead of it, in a sense waiting for the Earth to reach it, there can therefore be no question of any delay in the transmission of light through space.
Light does not contribute anything to this phenomenon, any aberration there may be lies, in consequence, in our senses and not in light itself: As the Earth approaches or recedes from the Sun, following a more or less elliptical course, the stars will appear to follow this movement on a smaller scale.
energy21.freeservers.com /fs8.htm   (5561 words)

 Zoom Astronomy Glossary: A
The aberration of light is a phenomenon in which light appears to be slanted (the angle at which the light appears to be coming is different than the angle at which it's actually coming) if the observer is in motion.
The aberration of light was discovered and demonstrated by James Bradley (an English amateur astronomer) in 1725.
The discovery of the aberration of light was one of the first proofs that the speed of light was finite; it also provided an early estimate of the speed of light (Bradley calculated that the time it took for light to travel from the Sun to the Earth was 8 minutes and 12 seconds).
www.zoomwhales.com /subjects/astronomy/glossary   (4918 words)

 Changes of Celestial Coordinates
The motion of Earth with a periodically varying direction of velocity is also responsible for the aberration of light, an apparent deviation of stars from their position with annual periodicity.
When light passes from one medium to another medium of different density (e.g., from the vacuum to Earth's atmosphere), the speed of light in the medium is changed (light is slower in the denser medium), causing the wavelengths of light to bend at different angles.
Refraction in Earth's atmosphere of light coming from a celestial object causes the object to appear in a slightly shifted position than it actually is; more acurately, objects near the horizon appear "lifted" to slightly higher altitudes.
www.seds.org /~spider/spider/ScholarX/coord_ch.html   (1035 words)

Ordinary light is a mixture of light of many different colors, i.e.
Because the refractive index of glass to light differs according to its color or wavelength, the position in which the image is formed differs according to color, creating a blurring of colors.
This chromatic aberration can be canceled out by combining convex and concave lenses of different refractive indices.
www.canon.com /technology/s_labo/light/003/02/004.html   (106 words)

 aberration — Infoplease.com
aberration, in optics, condition that causes a blurring and loss of clearness in the images produced by lenses or mirrors.
Spherical aberration is caused by the failure of a
Electron microscopes stand corrected: correction for the spherical aberration of lenses in electron microscopes is allowing scientists......
www.infoplease.com /ce6/sci/A0802146.html   (351 words)

 Aberration   (Site not responding. Last check: 2007-09-11)
In this section aberration is derived in a medium.
Though actually there are two aberrations, one by absolute motion of the observer and one by absolute motion of the source.
When a component of a light ray is perpendicular to the observer's absolute velocity v, there is an apparent change in direction of the light ray.
pw1.netcom.com /~heensle/phys/book/aberrat.html   (653 words)

 Aberration of light - Wikipedia, the free encyclopedia
However, it is important to understand the precise technical definition of these terms.
The difference between these two positions is caused mostly by aberration.
The sun and solar system are revolving around the center of the galaxy, as are other nearby stars.
en.wikipedia.org /wiki/Aberration_of_light   (2975 words)

 Speed of Light: Measurement
Early ideas about light propagation: Before the 17th century, scientists believed that there was no such thing as the "speed of light".
Today, according to the US National Bureau of Standards, the speed of light is = 299792.4574 +/- 0.0011 km/s.
However, according to Einstein's theory of General Relativity, the speed of light appears to vary with the intensity of the gravitational field.
www.speed-light.info /measurement.htm   (770 words)

 Stellar Aberration
In case of stellar aberration the light ray corresponds to the raindrops and the Earth corresponds to the moving car.
Both, speed vector of light and speed vector of Earth's are summarized, so that our eyes and optical instruments detect the resulting vector.
The phenomenon seems to deny Einstein's fundamental theory, the theory of relativity: Stellar aberration doesn't depend on the speed of source but the speed of observer only.
www.stormpages.com /gab33/stellar_aberration.htm   (623 words)

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