Chapter 7:
IR Imaging with WFC3

7.1 WFC3 IR Imaging

7.2 Specifying an IR Observation

7.3 IR Channel Characteristics

7.4 IR Field Geometry

7.4.1 Field of View and Pixel Size

7.4.2 Geometric Distortion

7.4.3 Coordinate Systems

7.4.4 Subarrays

7.4.5 Apertures

7.5 IR Spectral Elements

7.5.1 Filter and Grism Summary

7.5.2 Filter Blue Leaks

7.5.3 Ghosts

7.6 IR Optical Performance

7.6.1 PSF Width and Sharpness

7.6.2 Encircled and Ensquared Energy

7.6.3 Other PSF Behavior and Characteristics

7.7 IR Exposure and Readout

7.7.1 Exposure Time

7.7.2 MULTIACCUM Mode

7.7.3 MULTIACCUM Timing Sequences: Full Array Apertures

7.7.4 MULTIACCUM Timing Sequences: Subarray Apertures

7.8 IR Sensitivity

7.8.1 Limiting Magnitudes

7.9 Other Considerations for IR Imaging

7.9.1 Gain and Full-Well Saturation

7.9.2 Cosmic Rays and Snowballs

7.9.3 On-Orbit Degradation

7.9.4 Image Persistence

7.9.5 The IR Background

7.9.6 Blobs

7.9.7 Optical Anomalies

7.10 IR Observing Strategies

7.10.1 Dithering Strategies

7.10.2 Parallel Observations

7.10.3 Exposure Strategies

7.10.4 Spatial Scans

7.10.5 PSF Subtraction