Subaru's mission is to explore as
wide range of astronomical phenomena as possible, from
the birth and death of individual stars to the catastrophic
collisions of large galaxies.
Astronomical observations can be classified into two groups:
one is imaging objects to investigate their structure and
brightness, and the other is spectroscopy which spreads
light into its constituent colors to study temperature,
composition, and other physical characteristics. Optical
(visible) light and infrared light each probe different
astronomical phenomena. We can see stars and galaxies in
visible light, but we can only see into star-forming regions
enshrouded in thick dust by observing in infrared light.
Observational instruments are mounted at various foci of
the telescope and detect the light collected by the primary
mirror. Each instrument has special functions to explore
specific areas of frontier research. There are seven instruments
and an adaptive optics system that comprise the first-generation
instruments.
Subaru Telescope currently has seven observational instruments and an auxiliary in operation. Subaru Telescope's observational abilities, in visible light to infrared, are further more extended by MOIRCS, Multi-Object Infrared Camera and Spectrograph had first light in February 2006, and other four focus units.
 For
Scientists
Current Subaru Instruments
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Multi-Object Infrared Camera and Spectrograph (MOIRCS) |
MOIRCS is a wide-field imaging camera and spectrograph. The field of view is 4 x 7 square arcminutes with a spatial resolution of 0.117 arcsec/pixel projected on the sky. To achieve a wide view with high resolution, it uses two HAWAII-2 FPAs covering the focal plane.
Topics
(February 2006) MOIRCS First Light ! |
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Infrared Camera and Spectrograph
(IRCS) |
IRCS
is a workhorse infrared instrument for the Subaru
telescope, providing high angular resolution and sensitivity.
It is used in conjunction with the Adaptive Optics
unit. This instrument has the ability to separate light with a wavelength
difference of 1 part in 20,000. It was developed
under collaboration with the University of Hawaii.
This photograph shows the imaging optics. IRCS mounts
at the infrared Nasmyth focus.
Details
Topics
(June 2000) IRCS First Light ! |
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Coronagraphic Imager with
Adaptive Optics (CIAO) |
CIAO
is an instrument for imaging faint objects close
to much brighter objects such as searching planets
around other stars. It is a powerful instrument
when searching for planets around other stars. CIAO's
infrared detector and optics are kept cool within
a large vacuum container. CIAO mounts to the
Cassegrain focus. Details
Topics
(April 2000) CIAO First Light !
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Cooled Mid Infrared Camera
and Spectrometer (COMICS) |
COMICS
detects mid-infrared light between 10 and 20 μm.
It can be used to investigate the formation of planetary
systems, starbursts in external galaxies, and the
nature of interstellar dust particles. COMICS is
mounted at the Cassegrain
focus. Details
Topics
(January 2000) COMICS First Light !
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Faint Object Camera And
Spectrograph (FOCAS) |
FOCAS
is Subaru's workhorse instrument for high-sensitivity
optical observations. It is equipped with a multi-slit
system which allows spectra of up to 100 objects
to be taken simultaneously. This is a powerful capability
when measuring the distances to faint galaxies near
the edge of the Universe.
FOCAS attaches to the
Cassegrain focus. Details
Topics
(March 2000) FOCAS First Light ! |
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Subaru Prime Focus Camera
(Suprime-Cam) |
Suprime-Cam
mounts at Subaru's
prime focus where the field of view is 30 arcmin,
equivalent to the diameter of the full moon. By
simultaneously imaging such a large field, we can
efficiently perform studies of the formation and
evolution of galaxies and the structure of the Universe.
Suprime-Cam can also be used to search for Kuiper
Belt objects (small bodies at the edge of the Solar
System). It is a digital camera with a total of
80 million pixels, using 10 CCDs with 4096 x 2048
pixels each. Suprime-Cam was developed collectively
by School of Science & Institute for Cosmic
Ray Research, University of Tokyo and NAOJ. Details
Topics
(July 2000) Suprime-Cam at Prime Focus |
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High Dispersion Spectrograph
(HDS) |
HDS
splits light into its constituent colors with an
accuracy of 1 part in 100,000. With this precision,
we can investigate the evolution of elemental abundances
by observing old stars, as well as learn about the physical
and chemical state of intergalactic gas from quasar
absorption line studies. The instrument weighs 6
metric tons and sits at the
optical Nasmyth focus. Details
Topics
(August 2000) HDS First Light ! |
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Adaptive Optics (AO) |
The Subaru telescope has achieved
an
angular resolution of 0.2 arcsec at wavelength
of 2 μm by minimizing air turbulence
inside the enclosure. This resolution is, however,
still limited by atmospheric turbulence. With
the Adaptive Optics system, which can compensate
for the distorted wavefront very rapidly, the
light can be focused still further, limited only
by the diameter of the primary mirror. For many
observations, this limit of 0.06 arcsec exceeds
the resolution of the Hubble Space Telescope.
AO is mounted at the
Cassegrain Focus of the Subaru Telescope.
Details
Scientific
Results (December 2000) Adaptive Optics First
Light !
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Each of Subaru's seven instruments
detects light of either the optical or the infrared.
Instruments like FOCAS and IRCS function as both
a camera and a spectrograph. HDS specializes in
high resolution spectroscopy. The figure on the left shows
the wavelength regime detected by the instruments
above and how finely each can divide that light into component of
wave-lengths or colors (spectral resolution). Instruments
with different fields of view or special features
optimized for particular scientific targets sometimes
have overlapping wavelength and resolution coverage.
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Former Generation Instruments
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OH-Airglow Suppressor
(OHS) |
By eliminating infrared light emitted by OH airglow in the upper atmosphere, OHS achieves the high sensitivity required to obtain spectra of faint objects such as distant galaxies and brown dwarfs. It sits at the IR Nasmyth focus. This picture shows CISCO, the imaging camera for OHS, which has been working excellently since First Light.
Details
Topics (May 2000) OHS First Light !
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Guidelines
for Use of Subaru Images
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Wavelength Regime
