It was decided that the cameras with diffraction gratings over the lenses, the cameras that had been under development for a year, would suffice.
We brought back the idea of using an extremely long focal-length camera equipped with a diffraction grating.
We hoped that photos of the UFO's taken through the diffraction gratings would give us some proof one way or the other.
An instrument for measuring the diameters of minute particles or fibers, from the size of the colored rings produced by the diffraction of the light in which the objects are viewed.
One of a number of light or dark bands, produced by the interference of light; a diffraction band; -- called also interference fringe.
The subject generally is a curious one, and has interested me for some time; as experiments exhibit several singular phenomena resulting from the interference and diffraction of rays of light in passing by the outline of a material body.
There are two ways open to us--one by glass prisms, and the other by a diffraction grating.
The subject of diffraction is one into which it would be foreign to our purpose to wander.
We may say that for measures such as we shall make, it is handier to employ prisms, as the prismatic spectrum is more intense than the diffraction spectrum.
In some text-books it is told us that the diffraction grating gives us a dispersion which is in exact relation to the wave-length.
With two good prisms we use at last three-fourths of the incident light, so that for the same length of spectrum we can get at least three times the average brightness that we should get were we to employ a diffraction grating.
Light goes round a corner in these diffraction spectrums; it is shown going round a corner, it passes through these bars and is turned round an angle of thirty degrees.
This diffraction of light first proved to us definitely the reality of the undulatory theory of light.
Showing the chromatic bands thrown upon the screen from a diffraction grating.
I learned a year and a half ago that the lowest radiant heat observed by the diffraction method of Prof.
Light going round a corner by instruments adapted to show the result, and to measure the angles at which it is turned, is called the diffraction of light.
When in focus the central disc is surrounded by an intermittent diffraction pattern, i.
Irregular diffraction fringes point to bad annealing of the glass.
This was due to the diffraction of light by the exceedingly fine dust from the volcano, and the same phenomenon has been seen after other great explosive eruptions; e.
The diffraction phenomena of the atmosphere are produced by the water drops of clouds and fog, or sometimes by fine dust.
Krakatoa), are also explicable by the diffraction of light.
Other meteorological phenomena caused by the diffraction of light include the anthelia, and the chromatic rings seen encircling shadows thrown on a bank of clouds, mist or fog.
A diffraction grating, used for measuring the latter, has the lines so close together that they would be visible only under a powerful microscope.
The same method is employed to gauge the distance between the lines on a diffraction grating.
The only way in which this phenomenon can be accounted for is on the diffraction theory.
Hastings has proved that there must be diffraction where the corona is, and that it must follow the same laws as those observed.
But if diffraction is the cause of the light, then the slightest change in the relative positions of the sun and the moon should change the configuration of the corona, i.
Certain stones, when examined in thin sections by transmitted light, show a diffraction spectrum, due to the extreme delicacy of the successive bands, whence they are termed rainbow agates.
By this procedure the width of the central band in the diffraction pattern is halved, and so far an advantage is attained.
The contraction of the diffraction pattern with increase of aperture is of fundamental importance in connexion with the resolving power of optical instruments.
The first dark ring in the diffraction pattern of the complete circular aperture occurs when r/f = 1.
If the aperture and wave-length increase in the same proportion, the size and shape of the diffraction pattern undergo no change.
By supposing the retardation to vary uniformly and continuously we fall upon the case of an ordinary prism: but there is then no diffraction spectrum in the usual sense.
In applying the curve in special cases of diffraction to exhibit the effect at any point P (fig.
Diffraction when the Source of Light is not seen in Focus.
The results of the theory of the diffraction patterns due to circular apertures admit of an interesting application to coronas, such as are often seen encircling the sun and moon.
If the aperture be increased, not only is the total brightness over the focal plane increased with it, but there is also a concentration of the diffraction pattern.
On the electromagnetic theory, the problem of diffraction becomes definite when the properties of the obstacle are laid down.
The diffraction pattern is therefore that due to a single aperture, merely brightened n times.
In a diffraction spectrum the diffraction is proportional to the wave-length, and the spectrum is said to be "normal.
White light enters the dark room through a slit in the window-shutter, and falls in succession upon a grating and an achromatic lens, so as to form a real diffraction spectrum, or rather a series of such, in the focal plane.
Before quitting this subject it is proper to remark that Fresnel's bands are more influenced by diffraction than their discoverer supposed.
These are called diffraction colours, and are caused by minute lines upon the reflecting surface, or by thin transparent films.
Their slight amplitude, however, is the cause of there here being neither refraction nor diffraction phenomena, save in very special conditions.
It certainly appears, according to Professors Haga and Wind and to Professor Sommerfeld, that with the X rays curious experiments of diffraction may be produced.
The diffraction effects obtained in looking through a bird's feathers are, as shown by Schwerd, very brilliant.
The iridescence of certain Alpine clouds is also an effect of diffraction which may be imitated by the spores of Lycopodium.
The diffraction phenomena obtained during the artificial precipitation of clouds from the vapours of various liquids in an intensely illuminated tube are, as I have elsewhere shewn, exceedingly fine.
The street-lamps at night, looked at through the meshes of a handkerchief, show diffraction phenomena.
One of the most interesting cases of diffraction by small particles that ever came before me was that of an artist whose vision was disturbed by vividly coloured circles.
In the prismatic spectrum the less refrangible rays are compressed into a much smaller space than in the diffraction spectrum.
The name of diffraction is given to all the modifications which the luminous rays undergo when they come in contact with the surface of bodies.
The most interesting phenomena of diffraction are those presented by gratings, as are technically denominated the systems of linear and very narrow openings situated parallel to one another and at very small intervals.
It is therefore certain that this is a phenomenon of the diffraction of light simply produced by the vesicles of the mist.
In the diffraction spectrum, the order of the colours is reversed, red undergoing the greatest deviation; also, the deviation for a given colour is nearly proportional to the wave-length.
The diffraction spectrum is therefore termed a normal spectrum.
The septum spurium has been referred to as a temporary structure; the real division between the two auricles occurs at a later date than that between the ventricles and to the left of the septum spurium.
Deviations from the normal in the position or force of the apex beat will afford important information as to the nature of the pathological changes in the heart.
Perfect transparency is obtained since there is neither refraction nor diffraction of the visible colors.
He mounted the spectrometer and fell to work with a will, taking observations through the telescope, adjusting prisms and diffraction gratings, reading electrometers and other apparatus, and stopping to make intricate calculations.
