What is a spectrometer slit?

Apr 21, 2017 | Glossary of Spectroscopy Terms, Spectrograph

The slit is an opening that controls how much light enters the spectrometer. The width of the slit affects resolution; the narrower the slit, the higher the resolution. However, narrower slits also decrease signal strength. These two factors must be balanced when...

What is Full Width at Half Maximum (FWHM)?

Apr 21, 2017 | Characterization, Glossary of Spectroscopy Terms

The full width at half maximum (FWHM) is the width of a line shape at half of its maximum amplitude, as shown below: A closely related quantity is the half width at half maximum (HWHM) or the Resolving Resolution and it is half of the FWHM. For Gaussian line shapes,...

What is Spectrometer Sensitivity?

Apr 18, 2017 | Characterization, Glossary of Spectroscopy Terms

There are many different definitions of sensitivity. For StellarNet, we use the word sensitivity to mean the total system response of a spectrometer versus wavelength. This is a combination of the detector response, grating response, and any loss due to optics....

What is Resolution?

Mar 21, 2017 | Characterization, Glossary of Spectroscopy Terms

Broadly speaking, resolution is the ability to detect differences in measured units. For spectroscopy experiments, the measured unit is the quantity used to describe the photon (e.g. wavelength, wavenumbers, frequency, energy). For example, if the resolution of an...

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...