The MultiDrizzle Handbook

Chapter 4:
Astrometric Header Information

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4.1 HST Pointing Accuracy and Stability
    4.1.1 HST Pointing Accuracy
    4.1.2 HST Tracking Stability at a Single Location
    4.1.3 Precision of Commanded Offsets
    4.1.4 Pointing Repeatability After Guide Star Re-acquisition
    4.1.5 Roll Angle Repeatability Over Multiple Visits
4.2 Detector Plate scales and Geometric Distortion
    4.2.1 Introduction
    4.2.2 Summary of Detector Plate Scales
    4.2.3 Detector Distortion Models
    4.2.4 The IDC Table
    4.2.5 SIP Coefficients in the Image Headers
4.3 The CD Matrix
    4.3.1 Definition of the CD Matrix
    4.3.2 Computation of the CD Matrix
    4.3.3 Updating the WCS Header Information