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James Webb Space Telescope
NIRSpec at a Glance

Layout of NIRSpec

NIRSpec Features:

  • All Reflective Optics
  • 3.4ʼ x 3.6ʼ FOV (3' x 3' for Multi-object Spectroscopy)
  • 200 mas nominal slit width
  • 3 slit selection devices:
    • Micro-Shutter Array
    • Fixed slits
    • 3” x 3” Integral Field Unit
  • 3 spectral resolutions:
    • R=100 (0.7 - 5.0 µm - single prism)
    • R=1000 (1.0 - 5.0 µm - 3 gratings)
    • R=2700 (1.0 - 5.0 µm - 3 gratings)
  • 2 x 2k x 2k HgCdTe arrays

Sensitivity: The NIRSpec limiting sensitivity in 10,000 seconds for point source continuum at 3 µm for R=100 and at S/N=10 is AB=26.2. For the flux limit at 2m in 100,000 seconds is 5.2x10-19 erg cm-2s-1.