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Last Updated  Mar 24, 2017


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

Introduction

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

Click on the figure for a larger view.
NIRCam's 10
detectors are labeled. Each module has 5 detectors: 4 for the short wavelength channel and one for the long wavelength channel. Coronagraph images are projected onto the detectors by an optical wedge (when needed).


Optical path

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

Figure 2. NIRCam optical train

NIRCam optical train

Click on the figure for a larger view.
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

 

Click on the figure for a larger view.
Reproduced from Greenhouse et al. 2011, Figure 2.
 


 

Related links

Near Infrared Camera, NIRCAM

NIRCam Overview

NIRCam Dichroics

NIRCam Pupil and Filter Wheels

NIRCam Filters

NIRCam Weak Lenses

NIRCam Grisms

NIRCam Coronagraphic Occulting Masks and Lyot Stops

References

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

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JWST Observatory and Instrumentation