[Merlin66 (Ken)]

This spectroscope breaks light down into a coloured spectrum. The built in scale allows measurement of the various wavelengths of light across the spectrum from red and one end through to blue at the other.

At the entrance of the spectroscope there is an adjustable opening or slit, this can be made wider or narrower to suit the object/ light being viewed, the narrower the slit the more defined the detail in the spectrum. The other end has a small eyepiece lens which can be focussed to show the coloured specrum being formed.

It can be used to show the emmision bands ( in various colours in the spectum) of light sources like street light, chemicals, etc which then allow identification of the elements in the light source ie sodium, neon, etc.

When pointed towards a bright sky during the day it will show the spectrum of the Sun with all the dark absorbtion lines ( seen as dark lines across the various parts of the coloured spectrum) of the chemicals inside the sun. In the yellow region of the solar spectrum there are two neat black lines close together which are associated with the chemical sodium, these are called D1 and D2. This spectroscope can easily seperate these two lines.
For astronomy, it is usually held behind the eyepiece, (the telescope being focussed on a planet, star or other object), with the slit well open.

When used on stars, nebulae etc. it will show the brighter emmison lines of the elements in the stars, nebulae ie Hydrogen, oxygen, etc So it is possible to determine the type of star and its surface temperature. For planetary nebulae ( which are usually very small and difficult to distinguish from normal stars) it will allow easy identification... stars in the field of view become small spectra, the planetary nebulae being mostly hydrogen/ oxygen continue to show as a point star.

In schools they are widely used to show the nature of light and the spectra of various chemicals to students, in amateur astronomy they're used to study Solar, planetary stellar, comet, nebulae and galaxies and by analysing the light we get a better understanding of the nature of the universe. A spectroscope can also be used to test various filters to show which wavelengths of light are being passed through to the eye and which are being blocked ie Light pollution filters, OIII filters etc.

This small unit is an ideal starting point for this journey.