According to this view the chromatic effects depend entirely upon atmospheric dispersion.
These eyepieces are intentionally provided with a different chromatic magnification, which however is in opposition to that originating in the objective.
The chromatic rings seen encircling the "spectre of the Brocken" are similarly explained.
The most important is the chromatic difference of aberration of the axis point, which is still present to disturb the image, after par-axial rays of different colours are united by an appropriate combination of glasses.
In the interior the effect is gained by broad masses of chromatic decoration in marble-veneer and mosaics on a gold ground to cover the walls and vaults, and by elaborate pavements of opus sectile and opus Alexandrinum.
He did not attempt the formation of a parabolic figure on account of the probable mechanical difficulties, and he had besides satisfied himself that the chromatic and not the spherical aberration formed the chief faults of previous telescopes.
John Dollond, to whom the Copley medal of the Royal Society had been the first inventor of the achromatic telescope; but it was ruled by Lord Mansfield that" it was not the person who locked his invention in his scrutoire that ought to profit for such invention, but he who brought it forth for the benefit of mankind."3 In 1747 Leonhard Euler communicated to the Berlin Academy of Sciences a memoir in which he endeavoured to prove the possibility of correcting both the chromatic and.
White light) all these images are formed; and since they are all ultimately intercepted by a plane (the retina of the eye, a focussing screen of a camera, &c.), they cause a confusion, named chromatic aberration; for instance, instead of a white margin on a dark background, there is perceived a coloured margin, or narrow spectrum.
A system is said to be " chromatically under-corrected " when it shows the same kind of chromatic error as a thin positive lens, otherwise it is said to be " over-corrected."
For infinitely distant objects the radius of the chromatic disk of confusion is proportional to the linear aperture, and independent of the focal length (vide supra," Monochromatic Aberration of the Axis Point "); and since this disk becomes the less harmful with an increasing image of a given object, or with increasing focal length, it follows that the deterioration of the image is proportional to the ratio of the aperture to the focal length, i.e.
Instead of making d4 vanish, a certain value can be assigned to it which will produce, by the addition of the two lenses, any desired chromatic deviation, e.g.
Be cemented and have the same refractive index for one colour, then its effect for that one colour is that of a lens of one piece; by such decomposition of a lens it can be made chromatic or achromatic at will, without altering its spherical effect.
If its chromatic effect (d4/4) be greater than that of the same lens, this being made of the more dispersive of the two glasses employed, it is termed " hyper-chromatic."
While, however, the magnification of the individual zones is the same, it is not the same for red as for Blue; And There Is A Chromatic Difference Of Magnification.
The phenomena of chromatic polarization afford a ready means of detecting doubly refracting structure in cases, such as that produced in isotropic bodies by strain, in which its effects are very minute.
The Wilson has a greater distance between the lenses, and also a reduction of the chromatic difference of magnification, but compared with the Fraunhofer it is at a disadvantage with regard to the size of the free working distance, i.e.
By introducing a dispersive lens of flint the magnifying glass could be corrected for both chromatic and spherical aberrations.
The aberrations, both spherical and chromatic, increase very rapidly with the aperture.
In other words, a sufficiently good and distinct image as the resolving power permits cannot be arrived at, until the elimination, or a sufficient diminution, of the spherical and chromatic aberrations has been brought about.
This refers to systems with small apertures, but still more so to systems with large ones; chromatic aberrations are exceptionally increased by large apertures.
- Showing a system with chromatic difference of spherical aberration.
As powerful achromatic objectives show differences of chromatic magnification in the same way as apochromats, compensation eyepieces can be used in combination with these objectives.
The definition is better according as the chromatic and spherical aberrations are removed; there always remains in even the best constructions some slight aberration.
Of the chromatic substance between the two daughter nuclei.
Marine rainbow is the name given to the chromatic displays formed by the sun's rays falling on the spray drawn up by the wind playing on the surface of an agitated sea.
A similar feeling is shown by them as colorists, and, though sometimes eccentric and daring in their contrasts, they never produce discords in their chromatic scale.
Christiansen found, in an investigation of this kind, that the refractivity of the liquid could only be got to match that of the powder for mono-chromatic light, and that, if white light were used, brilliant colour effects were obtained, which varied in a remarkable manner when small changes occurred in the refractive index of the liquid.
The most interesting point about the morphology is the fact that two chromatic bodies, of very unequal size, are almost invariably to be recognized.
Fizeau he carried on a series of investigations on the intensity of the light of the sun, as compared with that of carbon in the electric arc, and of lime in the flame of the oxyhydrogen blowpipe; on the interference of heat rays, and of light rays differing greatly in lengths of path; and on the chromatic polarization of light.
The chromatic aberration of the object-glass of one of these telescopes is corrected for photographic rays, and the image formed by it is received on a highly sensitive photographic plate.
(b) Chromatic or Colour Aberration.
With this mineral also spherical and chromatic aberration are a fraction of that of a glass lens, but double refraction, which involves a doubling of the image, is fatal to its use.
When well made such constructions are almost free from spherical aberration, and the chromatic errors are very small.
Even in apochromats it is not possible to entirely remove the chromatic difference of magnification, i.e.
This method makes it specially possible to overcome the chromatic and spherical aberrations of higher orders and to fulfil – the sine-condition, and the chief merit of this improvement belongs to Amici.
In the apochromats the chromatic difference of the spherical aberrations is eliminated, for the spherical aberration is completely avoided for three colours.
There still remains a slight chromatic difference in magnification, for although the magnification consequent upon the fulfilment of the sine-condition is the same for all zones for one colour, it is impossible to avoid a change of the magnification with the colour.
Since, however, the difference of chromatic magnification cannot be overcome in powerful objectives, this error is still further increased by the eyepiece.
These, however, since they share the general lengthening or shortening of wave-length through motion, are thereby shifted, to a certain definite extent, into visibility, and so produce accurate chromatic compensation.
There are " chromatic differences " of the distances of intersection, of magnifications, and of monochromatic aberrations.
The Chromatic Differences Of Other Errors Of Reproduction Have Seldom Practical Importances.
But suddenly a storm came on, chromatic scales and diminished sevenths were heard in the orchestra, everyone ran off, again dragging one of their number away, and the curtain dropped.