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Introduction to Field of View Overlay for Roman

The Barbara A. Mikulski Archive for Space Telescopes (MAST) contains infrastructure to overlay the locations and shapes of instrument apertures on images, and to perform spatial footprint queries on catalog databases. This has enabled the creation of a web service, which can be executed remotely to visualize the Nancy Grace Roman Space Telescope Field of View (FOV), and to return catalog objects (e.g., GSC2, 2MASS, WISE) within specified detectors.

The user interface to this service is available on the MAST Catalogs and Surveys Group website.

The interface allows the user to specify target name and lookup coordinates from SIMBAD (Set of Identifications, Measurements, and Bibliography for Astronomical Data) or the Extragalactic Database (NED), or to input a position directly. Once a telescope/instrument/aperture combination is selected, the user can retrieve or display the footprint, as well as retrieve or display extractions from one of the available catalogs. The portal defaults to displaying the DSS as the background sky image, however, SDSS and GALEX imagery are also available.

M31 WFI overlay
WFI footprint on DSS image of Andromeda.
Roman instrument field of view layout
Phase C Reference Design
M31 2MASS overlay
All 2MASS Catalog sources present within the WFI footprint.


Known Limitations of the Prototype Tool

  • For the “Display Footprint” and “Display Catalog Data” functionalities to work, it may be necessary to set the browser preferences to allow pop-up windows (e.g. Safari, Chrome).
  • The “Display Footprint” function defaults to a size of 0.2 degrees at the center of the telescope’s focal plane, rather than at the location of the aperture. Since the WFI detectors have a significant offset from the center of the telescope's focal plane, the initial display will typically not show the aperture. The “Display Catalog Data” function defaults to center on the first object in the retrieved catalog list. Planned portal improvements will eventually allow specification of both the location and the size of sky display.
  • It is not possible to overlay both the aperture and the catalog on the same display. Planned improvements to the portal API will eventually eliminate this restriction.

Additional footprint-service help is available online or via email at the STScI Archive Help Desk.


Please contact with "FOV-Roman Question" in the subject line.


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