Glossary of Spectroscopy Terms - StellarNet, Inc.

What is a Concave Grating?

Mar 19, 2017 | Glossary of Spectroscopy Terms, Spectrograph

Plane (flat) gratings are prone to coma and astigmatism. Using multiple optics, as in the Czerny-Turner configuration, also increases the stray light. To minimize these errors, the BLACK-Comet spectrometer uses a concave grating. This means the three optics in a...

What is a Czerny-Turner Configuration?

Mar 19, 2017 | Glossary of Spectroscopy Terms, Spectrograph

The Czerny-Turner configuration is a specific arrangement of optics in spectrographs. There are other configurations, but Czerny-Turner is the most common. A majority of StellarNet spectrometers use the Czerny-Turner configuration. The diagram below shows the...

What is an Chromatic Aberration?

Mar 19, 2017 | Glossary of Spectroscopy Terms, Properties of Light, Spectrograph

Chromatic aberration is an aberration caused by dispersion. When a beam of light is transmitted through a lens, dispersion causes the wavelengths to focus at different focal points. The aberration can be corrected by adding other materials to essentially cancel out...

What is an Aberration?

Mar 19, 2017 | Glossary of Spectroscopy Terms, Properties of Light, Spectrograph

An aberration is when an optical system deviates from the expected ideal outcome. For example, lenses are expected to focus all rays of light to a single focal point. In practice, no lenses accomplish this. The cause of the deviation is called an aberration. In...

What is Wavelength (Spectral) Range?

Mar 19, 2017 | Glossary of Spectroscopy Terms, Spectrograph

The wavelength range (also called spectral range) is the range of wavelengths that each spectrometer can measure. StellarNet offers spectrometer options that cover a 190-2500nm wavelength range. Wavelength range is based on the spectrometers grating’s ability...

What is a Diffraction Grating?

Mar 19, 2017 | Glossary of Spectroscopy Terms, Spectrograph

Also called a grating for short, a diffraction grating is by far the most common dispersive element in spectrographs these days. As might be guessed, diffraction gratings work through diffraction. The gratings can be transmissive or reflective, but the principles are...