Spectroscope definitions and example sentences on Wordnik

View all »
Definitions (17)

American Heritage Dictionary (1)

noun An instrument for producing and observing spectra.

Century Dictionary (14)

An instrument used to produce a spectrum of the light (or, more generally, the radiation) from any source by the passage of the rays through a prism or their reflection from a grating, and for the study of the spectrum so formed. In its common form the essential parts of the prismatic spectroscope are—(1) a tube with a slit at the further end (see fig. 1), through which the light enters, and at the other end a collimating lens which brings the rays into a parallel beam (the slit is formed between two parallel edges the distance between which can be varied at will); (2) a prism to refract and disperse the rays, or a series or train of prisms when greater dispersion is desired—a gain, however, which is accompanied by a serious diminution in the intensity of the light; (3) a telescope through which the magnified image of the spectrum thus formed is viewed. A third tube is usually added, containing a scale, which is illuminated by a small gas-flame and reflected from the surface of the prism into the telescope, thus giving the means of fixing the position of the lines observed. A small glass comparison prism is often placed in front of half the slit, and through it, by total reflection, a second beam of light can be introduced, the spectrum of which is seen directly over the other. All instrument which gives a spectrum when the source of the light is in a straight line with the eye—that is, which gives dispersion without deviation—is called a direct-vision spectroscope (see fig. 2); this may be accomplished by combining two crown-glass prisms, with a third flint-glass prism of an angle of 90° between them (fig. 3). For certain rays—for example, the yellow—there is no divergence while a spectrum is obtained, since the dispersion of the flint-glass prism in one direction is greater than that of the two crown-glass prisms in the opposite direction. Other forms of direct-vision spectroscope have also been devised. In the grating spectroscope, or diffraction spectroscope, a diffraction-grating (a series of very fine parallel lines ruled on glass or speculum-metal) takes the place of the prism; and the parallel rays falling upon it are reflected, and form a series of diffraction-spectra (see diffraction, grating, 2, and interference, 5), which are called normal spectra (see spectrum, 3), since the dispersion of the rays is proportional to their wave-length. A prism is sometimes used before the telescope to separate parts of the snccessive spectra which would otherwise overlap. If a Rowland grating (see diffraction) is employed, the arrangements can be much simplified, since the large concave surface of the grating forms an image directly, which may be received upon a screen, or for stndy upon a photographic plate, or viewed through an eyepiece with cross-wires to fix the position of the lines observed. The grating is supported at one end of a rigid bar, in practice about 21 feet in length, at the other end of which, and at the center of curvature of the concave surface, is the eyepiece or support for the sensitive plate. The ends of this bar rest on carriages moving on two rails at right angles to each other; and, as the end carrying the eyepiece is moved, the whole length of the spectrum (several feet) may be successively observed, the fixed beam of parallel rays from the slit falling upon the grating as its position is slowly turned. The whole apparatus is mounted on rigid supports in a room from which all light but that received through the slit is carefully excluded. A high degree of dispersion is thus obtained, combined with the advantage of the normal spectrum, and the further advantages that the amount of light employed is large, while the disturbing effect of the absorption of the material of the prisms is avoided. See further under spectrum.
Analyzing spectroscope, integrating spectroscope terms applied to the spectroscope (Young) to describe its use, with or without a lens throwing an image of the luminous object npon the slit. In the former case, different parts of the slit are illuminated by light from different parts of the object, and their spectra can be separately compared, or, in other words, the light is thus analyzed; while in the second case, when the collimator is pointed toward the source of light, the combined effect of the whole is obtained.
Half-prism spectroscope a spectroscope in which the beam of rays enters the prism at right angles to one face, and suffers dispersion only on emerging from the face opposite and inclined to it. The half-prism ordinarily employed is half of a compound prism snch as is used in the direct-vision spectroscope.

11 more from this dictionary »

GNU Webster's 1913 (1)

WordNet (1)

Elsewhere on the web

View all »
Examples (50)

Now this is a spectroscope, OK, on my laboratory bench. — Luca Turin on the science of scent
Information provided by LIBS, however, is sometimes clouded by interfering signals caught by the spectroscope -- and eliminating the background can be expensive. — innovations-report
The instrument used for separating the rays of light in this way is called a spectroscope (Fig. — An Elementary Study of Chemistry
Now the simplest form of spectroscope is a glass prism--a triangular-shaped piece of glass. — The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told
And this applies also to the theories of the various stages through which the stars themselves pass on their way to extinction The light of about a quarter of a million stars has been analysed in the spectroscope, and it is found that they fall into about a dozen classes which generally correspond to stages in their evolution (Fig. — The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told

More examples »

spectroscope

View all »
Definitions (17)

American Heritage Dictionary (1)

Century Dictionary (14)

GNU Webster's 1913 (1)

WordNet (1)

Elsewhere on the web

View all »
Examples (50)

Tags

Stats

stop updating
On Twitter

Photos from

Add a related word »
Related

Used in the Same Context

Etymologies (2)

Century Dictionary (2)

Pronunciations
Record your own »

Charts

Recently looked up

Recent Favorites

Recent Pronunciations

spectroscope

View all » Definitions (17)

American Heritage Dictionary (1)

Century Dictionary (14)

GNU Webster's 1913 (1)

WordNet (1)

Elsewhere on the web

View all » Examples (50)

Tags

Stats

stop updating On Twitter

Photos from

Add a related word » Related

Used in the Same Context

Etymologies (2)

Century Dictionary (2)

Pronunciations Record your own »

Charts

Recently looked up

Recent Favorites

Recent Pronunciations

View all »
Definitions (17)

View all »
Examples (50)

stop updating
On Twitter

Add a related word »
Related

Pronunciations
Record your own »