The JWST NIRCam optical elements include dichroics, filters, weak lenses, grisms, as well as coronagraph occulting masks and Lyot stops.


Parent page: NIRCam Instrumentation

NIRCam's two modules (A and B) receive light relatively close to on-axis from the JWST Optical Telescope Element (OTE), as shown in the field of view in Figure 1.

Figure 1. NIRCam modules footprint in the JWST field of view

NIRCam modules in the JWST field of view

NIRCam's 10 detectorsare labeled. Each modulehas five detectors: four for the short wavelength channel and one for the long wavelength channel. Coronagraphimages are projected onto the detectors by an optical wedge (when needed).

Optical path

From the NIRCam pickoff mirror, within each module, light passes through these components in the following order:

Figure 2. NIRCam optical train

NIRCam optical train

Upper half of figure: NIRCam optical train
Bottom half of figure: the detector view, at the focal plane assembly (FPA), of incoming light, with and without a coronagraph wedge in the optical path. The coronagraph wedges are included on Lyot stop elements on each pupil wheel. Reproduced from Somerstein & Truong 2005.

Figure 3. NIRCam optical train in one module

NIRCam optical train in one module

Reproduced from Greenhouse et al. 2011, Figure 2.


Greenhouse, M. et al. 2011, SPIE 814606G
Status of the James Webb Space Telescope integrated science instrument module system

Somerstein, S. F., Truong, G.D. 2005, SPIE 590407
NIRCam optical calibration sources

Last updated

Published December 21, 2016

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Updated April 05, 2017

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Published March 02, 2017