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  2. Spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Spectroscopy

    Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers. Most spectroscopic analysis in the laboratory starts with a sample to be analyzed, then a light source is chosen from any desired range of the light spectrum, then the light goes through the sample to a dispersion array ...

  3. Optical spectrometer - Wikipedia

    en.wikipedia.org/wiki/Optical_spectrometer

    The spectrometer uses a prism or a grating to spread the light into a spectrum. This allows astronomers to detect many of the chemical elements by their characteristic spectral lines. These lines are named for the elements which cause them, such as the hydrogen alpha, beta, and gamma lines. A glowing object will show bright spectral lines.

  4. Stellar classification - Wikipedia

    en.wikipedia.org/wiki/Stellar_classification

    The spectral class of a star is a short code primarily summarizing the ionization state, giving an objective measure of the photosphere's temperature. Most stars are currently classified under the Morgan–Keenan (MK) system using the letters O , B , A , F , G , K , and M , a sequence from the hottest ( O type) to the coolest ( M type).

  5. Spectrum (physical sciences) - Wikipedia

    en.wikipedia.org/wiki/Spectrum_(physical_sciences)

    The spectral flux density is used to represent the spectrum of a light-source, such as a star. In radiometry and colorimetry (or color science more generally), the spectral power distribution (SPD) of a light source is a measure of the power contributed by each frequency or

  6. Spectral analysis - Wikipedia

    en.wikipedia.org/wiki/Spectral_analysis

    Spectral analysis or spectrum analysis is analysis in terms of a spectrum of frequencies or related quantities such as energies, eigenvalues, etc. In specific areas it may refer to: Spectroscopy in chemistry and physics, a method of analyzing the properties of matter from their electromagnetic interactions

  7. Spectral signature - Wikipedia

    en.wikipedia.org/wiki/Spectral_signature

    The spectral signature of an object is a function of the incidental EM wavelength and material interaction with that section of the electromagnetic spectrum. The measurements can be made with various instruments, including a task specific spectrometer , although the most common method is separation of the red, green, blue and near infrared ...

  8. Spectrometer - Wikipedia

    en.wikipedia.org/wiki/Spectrometer

    An XPS spectrometer. A spectrometer (/ s p ɛ k ˈ t r ɒ m ɪ t ər /) is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the spectral components are somehow mixed.

  9. Spectral density - Wikipedia

    en.wikipedia.org/wiki/Spectral_density

    This is the basis of a number of spectral analysis techniques such as the short-time Fourier transform and wavelets. A "spectrum" generally means the power spectral density, as discussed above, which depicts the distribution of signal content over frequency.