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Observatory Overview

The Nancy Grace Roman Space Telescope will have sensitivity and resolution comparable to the Hubble Space Telescope, but with a field of view 200 times greater than Hubble's infrared view, combining excellent image quality with survey power. The Roman Space Telescope observatory will utilize an existing 2.4-meter AFTA (Astrophysics-Focused Telescope Assets) telescope, donated to NASA by another agency, and will be located at the second Sun-Earth Lagrange point (L2).

The prime mission is five years with a goal of ten years. Read more about the key mission characteristics

Artistic rendering of WFIRST and Mirror Assembly
Depiction of the Roman Space Telescope in Flight (left) and image of the Roman Telescope Primary Mirror (right). Credit NASA/GSFC


Roman has two instruments to execute the mission science program:

Wide Field Instrument (WFI)

The Wide Field Instrument (WFI) will operate in the 0.5–2.3 micron range. The WFI will have eight imaging filters, a grism, covering the wavelength range between 1.00 and 1.93 micron at a resolution of R=460, and a prism, covering the 0.75-1.80 micron range at a resolution R=80-180.

More about the Wide Field Instrument

Coronagraph Instrument

The Coronagraph Instrument will operate in the 0.4–1.0 micron range. This Technology Demonstration instrument will offer an imaging mode, a single slit spectroscopic mode with a prism, and polarimetric capabilities. The Coronagraph Instrument was added to the mission as a “New Worlds Technology Development Program,” which was the top medium-scale priority in space described in the NWNH Decadal Survey Report.

More about the Coronagraph Instrument

Roman Capabilities

The tables below detail the imaging, spectroscopic, and corographic capabilities of Roman. Additional information can be found on the GSFC website.

Wide Field Instrument: Imaging
Telescope Aperture Field of View Pixel Scale Wavelength Range
2.4 meter 45'x23'; 0.28 sq deg 0.11 arcsec 0.5-2.3 µm


Filters F062 (R) F087 (Z) F106 (Y) F129 (J) F146 (I/H)   F158 (H) F184 (H/K) F213 (Ks)
Wavelength (µm) 0.48-0.76 0.76-0.98 0.93-1.19 1.13-1.45 0.93-2.00 1.38-1.77 1.68-2.00


(5σ AB mag in 1 hr)
27.9 27.6 27.5 27.5 27.9 27.4 26.7




Wide Field Instrument: Spectroscopy
Continuum Sensitivity (AB mag)
(5σ per pixel in 1hr)
Grism 1.00-1.93 21.4 at 1.5 µm 461
Prism 0.75-1.80 23.5 at 1.5 µm 80-180


Coronagraph Instrument: Imaging and Spectroscopy
Estimated Detection Limit Spectral Resolution Inner Working Angle
Outer Working Angle
Imaging 0.5-0.8 10-9 contrast
(after post processing)
  exoplanets: 0.15
disks: 0.48
exoplanets: 0.66
disks: 1.46
Spectroscopy 0.675-0.785   47-75    

Citation: Roman Reference Information (Phase C payload design)

Additional Resources


Nancy Grace Roman Space Telescope insignia

The NASA Nancy Grace Roman Space Telescope is managed by NASA/GSFC with participation of STScI, Caltech/IPAC, and NASA/JPL.

Contact the Roman Team