What is a spectroscope?
The espectroscope It is a tool that is used to be able to carry out an analysis of light, by means of which data can be obtained on the number of physical characteristics or the characteristics of objects, including Stars. They are used in a wide variety of areas, ranging from theoretical studies in sciences such as chemistry or quantum physics, as well as in industrial or medical fields. In this sense, knowing the scientific methods It is key to understanding its operation and applications.
Origin of the spectroscope
In its origins, spectroscopes had prismatic forms of glass inside, with which the dispersion of light emissions could be obtained, because the different angles of refraction that the different colors have were used for it, today we know which are observable by wavelengths of white light.
Likewise, diffraction zones were used for this same purpose, which is another peculiarity with which the division of the emanations that are radiated in the form of white light can be achieved.
It is said that the invention of the first spectroscope It is due to two German researchers, Robert Bunsen and Gustav Kirchhoff, in the mid-nineteenth century. But the truth is that several scientists developed very similar devices in previous years, some of which constituted tests that were used in experiments to analyze the spectra resulting from chemical analyses.
Joseph von Fraunhofer
Proof of this is that at the beginning of the 1787th century, Joseph Von Fraunhofer (1826-XNUMX) made relevant contributions to the investigation of the solar spectrum and the structure of the sun, with which he could see a number of black lines that today bear his name. These Fraunhofer experiments were the product of his curiosity to find a homogeneous light source for the proper functioning of his optical instruments.
Thanks to the activity of all these researchers, it was possible to give a boost to the study of spectra or emanations by researchers who were interested in new theories about the undulation of light and the characteristics of electric sparks.
william talbot
The use of spectra for the analysis of chemical substances had the intervention of some precursors such as William Talbot (1800-1877) who, after having studied the various emanations of flames, his conclusions led him to assert that whenever the prism shows that a homogeneous ray of any color is present in a flame, such a ray shows the existence of a definite chemical element.
Despite the number of these pioneering experiments, their application was very limited, mainly because of the theoretical and practical problems that had not yet been solved. One is that various spectra of the flames had a more complex appearance than initially concluded. In fact, the Fraunhofer emanations or lines did not yet have a plausible scientific explanation.
william swan
In the XNUMXs, several factors came together to exponentially increase scientific experiments on light spectra, including those carried out by William Swan, who was a professor at the Scottish Naval and Millitary Academy, with whom he colluded the high sensitivity of spectral analysis, allowing it to detect very small amounts of some chemical elements such as sodium.
These experiments allowed him to explain the usual presence of the sodium D line and establish the need to work with extreme caution, in relation to the purity of the samples and the flames used. An instrument that helped to solve some of these problems was the burner created by Bunsen in those years.
Constitution and Parties
El spectroscope It is composed of a prism, a collimator, and a telescope, the optimum of which is achromatic, which facilitates clear observation of the entire spectrum. These parts are rigidly attached to the central body of the device, connecting it to a metal base using a height-adjustable column. In its lower central section, we find a device that supplies light to scale. It is interesting to note that these instruments can be part of a homemade spectroscope.
The ECYT 12-810 Spectroscope
The elements of this spectroscope are the following:
- Flint glass equilateral triangular prism (n=1.65)
- Collimator composed of a fixed slot (0.2mm) and a system of achromatic lenses arranged on a 25x100mm aluminum tube.
- Observation telescope, formed by an achromatic objective arranged on the aluminum tube and objective mounted on a chromed bronze tube with scale included.
- Central or cylindrical body, 90mm in diameter, 50mm thick.
- Support base, rectangular 100x150mm, with brake system for fixing the column, in painted cast iron.
- 15x130mm chromed iron cylindrical column.
- Scale illuminator, with diffuser screen
Operating principle
There is a great variety of methods, strategies and techniques linked to the use of spectroscope, For this reason, a great variety of types have been created, which have very different characteristics, so that it may have certain difficulties to recognize the existence of some common characteristics or principles.
El spectroscope It has the function of breaking down the incident light, separating it into different radiations or monochromatic emissions, with this it is possible to directly observe the light spectrum of a certain element. Dispersion or decomposition can be obtained by means of refraction, as occurs in the case of prism spectroscope or by diffraction, which is what happens with the spectroscope network.
Prism Spectroscope
The formation of spectroscope A prism consists of a slit through which light passes, through grouped lenses, towards a prism and an eyepiece lens. The light that enters to be analyzed falls first through a collimating lens, which causes a narrow and parallel beam of light, and then passes through the prism, where this beam is separated into the different monochromatic radiations that compose it.
Thanks to the eyepiece lens, an image is focused on the slit. Thus, the spectral lines that form the spectrum are actually nothing more than a series of images of the slit. This phenomenon is similar to that observed in arco iris which is shown in periods of rain but with the presence of adequate sunlight, so that the raindrops perform the function of small prisms that separate the different radiations.
Network Spectroscope
El spectroscope A grating is one that disperses light using a diffraction grating, instead of using a prism. The diffraction grating is a specular surface, which can be made of metal or glass, on which many very fine parallel lines have been drawn with a diamond. The advantage of this type of spectroscope is that it has a greater dispersion power than a prism, which favors a more detailed observation of the spectra.
Types of Spectroscopes in History
There are many types of spectroscopes, but we will mention the most relevant by historical periods:
- Spectroscope designed by French manufacturer Jules Duboscq
- Anders Jonas Angstrom (1814-1874) spectrometer that he used to study the spectrum of the Sun that appeared in 1868.
- Kew Observatory spectroscope, used for the study of the solar spectrum
- Constant deviation spectroscope manufactured by the London company Adam Hilger
