Astrophysics (index)about

imaging spectrometer

(imaging spectrograph)
(device to capture spectrum point-by-point of an image)

An imaging spectrometer is a spectrometer that collects spectral data over a two-dimensional area, i.e., for each part of the image, information about the intensity for each wavelength is determined. This produces a "cube" of data (three dimensions), two being spatial (the image) and one being the spectral data at the specified point.

There are various types: a common type for astronomy is the integral field spectrograph which incorporates a device called the integral field unit to arrange pieces of the two dimensional image along a line, i.e., one dimension. Common spectrometers use a slit to image and measure the spectrum across a line selected from the telescope's two-dimensional image, so the resulting graph (photo or electronically stored image) displays spectral data in one direction (the spectral direction or dispersion direction) and spatial information over just one dimension in the other (the spatial direction). By the rearranging the image so as to place image-portions across a two-dimensional area so they are in a line, the same spectrograph can capture spectrums of the whole image at a lower spatial resolution. Lenses, prisms, and/or fiber can be used to accomplish the rearrangement. This constitutes a time-saver compared to taking a series of snapshots with a "normal" spectrometer, shifting the slit each time to capture the second spatial dimension.

Another type of imaging spectrometer is an imaging Fourier transform spectroscopy.

Be warned that the term imaging spectrograph has been used for something else: spectrographic instruments may offer the option of bypassing the prism or grating, so as to use its camera for (non-spectroscopy) imaging and such an instrument may be described as an "imaging spectrograph" (e.g., the Hubble Space Telescope's STIS) even though in spectrograph-mode, it views only the typical long-slit single dimension.


(color,EMR,instrument type)
http://en.wikipedia.org/wiki/Imaging_spectrometer
http://en.wikipedia.org/wiki/Integral_field_spectrograph
http://www.geo.uzh.ch/microsite/rsl-documents/research/publications/book-chapters/2009_Spectrometers_HandbookRS_MS-3188925952/2009_Spectrometers_HandbookRS_MS.pdf
http://www.ucolick.org/~bolte/AY257/ay257_5a.pdf
http://www.astro.caltech.edu/~george/ay122/Ay122a_Spectroscopy.pdf

Referenced by:
ACIS
Cassini
CCAT-prime (CCAT-p)
Chandra X-ray Observatory (CXO)
COMAP
Europa Clipper
Gemini Observatory
Hale Telescope
imaging Fourier transform spectroscopy (IFTS)
interferometry
JUICE
Juno
Keck Observatory
Large Binocular Telescope (LBT)
linearly variable filter (LVF)
Mars Reconnaissance Orbiter (MRO)
multi-object spectrograph
New Horizons (NF1)
position-position-velocity space (PPV)
Rosetta
Solar Maximum Mission (SMM)
spectroscopy
STARFIRE
Suzaku
Thirty Meter Telescope (TMT)
James Webb Space Telescope (JWST)

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