Spectroscopes Sentence Examples
Angular prism spectroscopes are the commonest.
In grating spectroscopes both plane and concave gratings are employed in connexion with a collimator and observing telescope.
Rutherfurd devised one made of flint glass with two crown glass compensating prisms; whilst Thallon employed a hollow prism containing carbon bisulphide also compensated by flint glass prisms. In direct vision spectroscopes the refracting prisms and slit are in the observing telescope.
We readily find (with substitution for k of 27r/X) a2b S n J s in fl „2a2E2 „2b2n2 f2X2 f2X2 as representing the distribution of light in the image of a mathematical point when the aperture is rectangular, as is often the case in spectroscopes.
The instruments which effect such a resolution are called spectroscopes.Advertisement
But the spectroscopes that can be employed for stellar spectroP graphs are not sufficiently powerful to separate fully lines which are very closely adjacent, and therefore a line, assumed to be of a known wave-length, may be apparently displaced by the near neighbourhood of an unknown line.
The formula expressing the optical power of prismatic spectroscopes may readily be investigated upon the principles of the wave theory.
If, as in common flint-glass spectroscopes, there is only one dispersing substance, f Sy ds = Sµ.s, where s is simply the thickness traversed by the ray.
It follows that for observations in which light is a consideration spectroscopes should be used which give about twice the resolving power of that actually required; we may then use a slit having a width of nearly eight times that of the normal one.
This analogy is useful because the application of Fourier's analysis to the optical theory of spectroscopes has been doubted, and it may be urged in answer to the objections raised that the instrument acts in all respects like a mechanical analyser,' the applicability of which has never been called into question.Advertisement
The bands often appear in groups, and such spectra containing groups of bands when viewed through small spectroscopes sometimes give the appearance of the flutings of columns.