JWST Field of View

Each JWST instrument observes an area on the sky bounded by the coordinates given in the telescope's (V2, V3) coordinate system.

Figure 1 shows NIRSpec, NIRCam, MIRI, NIRISS, and FGS fields of view in the JWST focal plane.  

Table 1 provides the vertices of each region in the observatory's coordinate system (V2, V3).  This is a small excerpt of data from the JWST Science Instrument Aperture File (SIAF).  SIAF is a reference file used in operations that contains the official information on all apertures (e.g., NIRCam Apertures) and internal instrument coordinates.

Figure 1. The JWST field of view

Each JWST instrument observes an area on the sky shown here in (V2, V3) coordinates. Colors indicate observing modes: imaging, coronagraphy, grism spectroscopy, slit spectroscopy, NIRISS AMI, NIRSpec MSA, NIRSpec IFU, MIRI MRS (IFUs), and guidance with FGS.
The SIAF excerpt table below provides the following information for various apertures defined for each instrument:

  • (V2_Ref, V3_Ref) is the reference position in (V2, V3) coordinates (arcsec); some of these entries are used to define telescope pointings.
  • V3_IdlYAngle is the rotation (in degrees, counterclockwise) of the aperture's ideal Coordinate System Y-axis relative to V3.
  • (V2_1, V2_2, V2_3, V2_4), (V3_1, V3_2, V3_3, V3_4) are the vertices in the (V2, V3) coordinates (arcsec) of the quadrilateral defined by each aperture.

For a few of the instruments, larger bounding box apertures are excluded from the plot above but included in the table below (marked with *).

The coordinates given below are approximate and subject to frequent minor revisions.  More significant revisions are expected after launch based on flight data.


Table 1. Approximate coordinates (V2, V3) of select instrument apertures

Scroll right and down to view the full table.

InstrumentApertureV2_RefV3_RefV3_IdlYAngleV2_1V2_2V2_3V2_4V3_1V3_2V3_3V3_4
NIRCamNRCALL_FULL*-0.32-492.59-0.03153.16-153.74-152.07151.38-559.27-557.14-426.00-427.95
NIRCamNRCAS_FULL*81.35-498.23-0.10153.1619.4920.80151.38-559.27-560.22-428.00-427.95
NIRCamNRCA1_FULL120.67-527.39-0.57153.1688.9088.69152.08-559.27-559.88-495.59-495.15
NIRCamNRCA2_FULL120.11-459.68-0.21151.9588.5688.68151.38-491.11-491.49-428.17-427.95
NIRCamNRCA3_FULL51.93-527.800.1984.0519.4920.1583.83-560.03-560.22-495.59-495.73
NIRCamNRCA4_FULL52.28-459.810.0684.0020.3920.8083.71-491.46-491.59-428.00-428.20
NIRCamNRCA5_FULL86.10-493.23-0.09151.4520.8822.23149.72-557.79-558.60-428.46-428.63
NIRCamNRCBS_FULL*-82.29-496.21-0.06-20.32-153.74-152.07-21.93-558.08-557.14-426.00-425.81
NIRCamNRCB1_FULL-120.97-457.750.38-89.59-152.82-152.07-89.52-489.58-489.07-426.00-426.35
NIRCamNRCB2_FULL-121.14-525.460.83-89.55-153.74-152.37-89.05-558.09-557.14-493.08-493.86
NIRCamNRCB3_FULL-53.12-457.78-0.49-21.05-84.57-84.75-21.93-489.32-489.59-426.40-425.81
NIRCamNRCB4_FULL-52.82-525.73-0.34-20.32-84.82-84.77-21.16-558.08-557.99-493.71-493.47
NIRCamNRCB5_FULL-89.39-491.44-0.01-23.98-154.75-153.25-25.54-556.87-556.16-426.75-426.52
NIRCamNRCA2_MASK210R127.23-405.24-0.24137.11117.44117.39137.00-415.05-415.17-395.46-395.36
NIRCamNRCA5_MASK335R107.51-405.52-0.19117.5697.5997.55117.47-415.45-415.55-395.51-395.43
NIRCamNRCA5_MASK430R87.25-405.19-0.0197.2777.2977.3297.24-415.17-415.19-395.13-395.13
NIRCamNRCA4_MASKSWB67.61-404.67-0.0877.4657.7557.7677.40-414.53-414.57-394.82-394.81
NIRCamNRCA5_MASKLWB47.20-405.440.3557.2037.1337.2957.30-415.52-415.40-395.28-395.43
NIRISSNIS_CEN-290.10-697.50-0.57-222.43-356.38-357.71-223.78-764.48-765.25-630.26-629.60
NIRISSNIS_AMI1-293.74-762.31-0.57-290.73-295.96-296.02-290.79-764.96-764.99-759.72-759.69
NIRSpecNRS_FULL_IFU_IFU300.15-498.12138.89295.63300.55304.96300.05-497.56-493.15-498.24-502.65
NIRSpecNRS_S200A1_SLIT332.14-479.22138.76329.66329.82331.90331.75-478.13-477.99-480.38-480.51
NIRSpecNRS_S400A1_SLIT321.87-477.94138.78319.10319.48321.91321.52-476.84-476.49-479.27-479.61
NIRSpecNRS_S200A2_SLIT314.98-489.45138.83312.42312.65314.73314.50-488.46-488.26-490.64-490.85
NIRSpecNRS_S1600A1_SLIT321.53-473.68138.77319.11320.26321.30320.15-473.72-472.69-473.88-474.91
NIRSpecNRS_S200B1_SLIT440.48-364.52138.16437.76437.92440.10439.95-363.55-363.41-365.83-365.97
NIRSpecNRS_FULL_MSA*378.77-428.16138.49223.34385.55534.72368.50-418.79-275.00-439.02-586.32
NIRSpecNRS_FULL_MSA1466.48-436.16138.24398.68472.27535.09460.68-434.47-369.74-438.70-504.11
NIRSpecNRS_FULL_MSA2381.89-340.89138.30313.41385.93446.75373.49-338.63-274.66-341.68-406.16
NIRSpecNRS_FULL_MSA3375.82-516.37138.74307.26380.36442.15368.26-515.99-450.72-520.54-586.53
NIRSpecNRS_FULL_MSA4291.77-420.64138.69223.11295.32355.24282.44-418.99-354.67-422.35-487.32
MIRIMIRIM_FULL*-453.36-374.070.08-381.41-494.97-486.22-372.61-436.72-427.34-315.00-323.34
MIRIMIRIM_ILLUM-453.36-374.070.08-420.52-494.42-485.67-411.71-433.61-427.39-315.04-320.33
MIRIMIRIM_MASK1065-393.11-421.180.08-381.24-412.55-410.66-379.20-434.74-432.26-407.47-409.96
MIRIMIRIM_MASK1140-391.12-396.530.08-379.18-410.64-408.74-377.22-409.73-407.25-382.44-384.91
MIRIMIRIM_MASK1550-389.22-372.030.08-377.24-408.75-406.82-375.33-385.13-382.66-357.86-360.30
MIRIMIRIM_MASKLYOT-389.09-337.610.08-375.11-410.13-407.44-372.64-357.42-354.72-321.09-323.79
MIRIMIRIM_SLIT-414.33-400.694.36-411.99-416.72-416.68-411.95-401.14-400.76-400.24-400.62
MIRIMIRIFU_FULL_SHCH1CNTR_CH4-504.48-321.0617.00-502.41-508.81-506.55-500.15-325.74-323.78-316.38-318.34
FGSFGS1_FULL207.19-697.50-0.02280.66138.36136.62275.96-771.81-769.86-626.68-627.03
FGSFGS2_FULL24.43-697.500.0094.31-46.78-44.8693.43-769.39-771.74-627.78-626.34



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