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WFC3 Instrument Handbook
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Wide Field Camera 3 Instrument Handbookfor Cycle 22 > Chapter 7: IR Imaging with WFC3 > 7.3 IR Channel Characteristics

7.3
The WFC3 IR channel has been optimized for observing over the wavelength range 800-1700 nm. All the IR reflective optics (except for the WFC3 pick-off mirror) are coated with a silver layer for maximum IR throughput.
A schematic mechanical diagram showing both channels of WFC3 is given in Figure 2.1. Components of the IR channel include: the Channel Select Mechanism (CSM), which directs on-axis light from the HST OTA to the IR channel; a flat folding mirror; a two-mirror mechanism for providing focus and alignment adjustments; the Refractive Corrector Plate (RCP), which applies the spherical-aberration correction; the IR filter wheel (FSM or Filter Selection Mechanism); and finally the HgCdTe IR detector package.
The WFC3 IR detector is a HgCdTe 10241024 array, with 18 micron pixels, bonded to a silicon multiplexer, with 10141014 pixels sensitive to incoming light. It is a direct descendant of the NICMOS 256256 and Hawaii-1 10241024 arrays (more details on the detector are given in Chapter 5).

Wide Field Camera 3 Instrument Handbookfor Cycle 22 > Chapter 7: IR Imaging with WFC3 > 7.3 IR Channel Characteristics

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