Astrophysics (Index)About

multi-object spectrograph

(multi-object spectrometer)
(device to record the spectrum of multiple targets simultaneously)

A multi-object spectrograph is a spectrograph designed to collect spectrographic data from multiple targets simultaneously. The term is commonly used for spectrographs connected to the focal plane by multiple optical fibers: at the focal plane, the fiber end is located at the position of the image of the target source, and at the spectrograph, the fiber ends are in a line along the spectrograph's slit. Such instruments have been built that can handle as many as five hundred targets simultaneously. The Sloan Digital Sky Survey (SDSS) used such a spectrograph, in its initial phases, using pre-created plates with holes so at the time of observation, the fibers could be quickly and accurately positioned to catch the target sources. Automated fiber positioners are now used for advanced models, which position the fibers based upon the targets' coordinate data. Both the spectrograph and fiber positioner are complicated and expensive, often requiring years to design, build, and commission. However, the efficiency of gathering hundreds of spectra at a time is a significant advancement for astronomy. Telescopes/instruments using this:

The term multi-object spectrography indicates observation with such instruments.

Among older strategies (which predate the common use of the term multi-object spectrograph) is use of a slitless spectrograph, which could produce a number of small "rainbows" on a photographic plate, a strategy was used in some earlier star surveys. Color photography was not used: by inspecting the line produced by each star, some spectral characteristics could be discerned. Another strategy has been to use a mask that has slits positioned for a number of individual targets rather than a single slit.


(color,EMR,instrument type,spectrography)
Further reading:
https://en.wikipedia.org/wiki/Fibre_multi-object_spectrograph
https://en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph
https://en.wikipedia.org/wiki/Slitless_spectroscopy
https://ui.adsabs.harvard.edu/abs/2016SPIE.9908E..1SC/abstract
https://giantmagellan.org/scientific-instruments/multi-object-spectrograph/
https://www.eso.org/sci/facilities/paranal/instruments/flames/inst/Giraffe.html

Referenced by pages:
2dF Galaxy Redshift Survey (2dFGRS)
2dF-SDSS LRG and QSO survey (2SLAQ)
4MOST
BigBOSS
Dark Energy Spectroscopic Instrument (DESI)
Dark Energy Survey (DES)
ESO Nearby Abell Cluster Survey (ENACS)
European Extremely Large Telescope (E-ELT)
European Southern Observatory Very Large Telescope (ESO VLT)
fiber positioner
Gaia
GAMA
Giant Gemini GMOS survey (GGG survey)
Gran Telescopio Canarias (GTC)
H3 Survey (H3)
HERMES
Hiltner Telescope
Hubble Space Telescope (HST)
James Webb Space Telescope (JWST)
Keck Observatory
KMOS
Las Campanas Redshift Survey (LCRS)
Magellan Telescopes
Mayall 4m Telescope
Milky Way Mapper (MWM)
MMT
Multi-object Optical and Near-IR Spectrograph (MOONS)
NIRSpec
photometric redshift (photo-z)
PRIMUS
Roman Space Telescope (RST)
slitless spectrograph
Sloan Digital Sky Survey (SDSS)
spectroscopy
Subaru PFS
Subaru Telescope
TAIPAN
Thirty Meter Telescope (TMT)
UK Schmidt Telescope (UKST)
Víctor M. Blanco Telescope
VIMOS-VLT Deep Survey (VVDS)
VISTA
WEAVE
Wide-field Multi-object Spectrograph (WFMOS)
William Herschel Telescope (WHT)

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