About the Subaru Telescope

Observational instruments

Multi-Object Infrared Camera and Spectrograph (MOIRCS)

Multi-Object Infrared Camera and Spectrograph (MOIRCS)

MOIRCS is a near-infrared camera and spectrograph that combines a wide field of view with the capacity to capture the spectra of about 40 objects simultaneously. Its most notable feature is its multi-object spectroscopy, which opens a large window to the Universe by allowing researchers to obtain infrared spectra for a large number of objects in a single observation.

Fast Facts


  • Infrared camera and spectrograph
  • Wide field of view
  • Three principal structures
  • Main cryostat
  • Multiple-object mask exchange system
  • Support frame


  • Camera
  • Mirrors split incoming light and send different parts of image to two detectors.
  • Tohoku University Focal Plane Array Controller (TUFPAC) produces images
  • Spectrograph
  • Capable of obtaining multiple spectra of up to 40 astronomical objects at the same time, marking a dramatic increase in observational efficiency over single object spectroscopy
  • Mask carousel
  • Has up to 21 mask slots for multi-object spectroscopy.
  • Can switch between two masks in 4 minutes.
  • Separated from main instrument structure so that new masks can be put on without opening the entire instrument.


  • Exploration of objects at the far reaches of the Universe
  • Large numbers of distant galaxies
  • Large structures, e.g., nearby nebulae


  • Size and weight:
  • 2 m x 2 m x 2 m (7 ft. x 7 ft. x 7 ft.)
  • 2.3 tons
  • Placement: Cassegrain focus
  • Detectors used: two, 4 megapixel Hawaii II detectors (2048 x 2048)
  • Filters available for imaging and spectroscopy: Y, J, H, K bands
  • Wavelengths: near-infrared between 0.9 and 2.5 microns
  • Fully cryogenic
  • FOV: 4 x 7 arcminutes
  • Spectral resolution in three modes
  • Low (R~400)
  • Medium (R~1300)
  • High (R~3000)
  • Spatial Resolution: 0.117 arcsecond


  • Co-developed by Subaru Telescope (National Astronomical Observatory of Japan) and Tohoku University.
  • Research and development began in 1999 with significant contributions by graduate students.
  • Overcame several challenges, e.g., developing a drive mechanism for the mask that could withstand cryogenic conditions of at least minus 150 degrees.
  • Tohoku University Focal Plane Array Controller (TUFPAC) software was developed at Tohoku University.
  • Construction began in 2000.
  • Handbuilt from individually procured high-performance parts
  • Was the world's first multi-object near-infrared spectrograph available for common use on a large (8-10 m) telescope.
  • "nuMOIRCS" Project scheduled for 2015
  • Introduction of integral field spectroscopy (IFU) function to MOIRCS
  • Change detectors to Hawaii II RG
  • Replacement of all electronics related to the detectors

Specialized Information about the Instrument and Observing: