HST Data Handbook for NICMOS

Chapter 5:
Data Analysis

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5.1 STSDAS Software
5.2 The NICMOS History Tool
5.3 Photometric Calibrations
    5.3.1 Units for NICMOS Photometry
    5.3.2 Fluxes and Magnitude Zeropoints
    5.3.3 Photometric Corrections
    5.3.4 Absolute Photometry for Emission Line Filters
    5.3.5 Absolute Spectrophotometry with NICMOS Grisms
5.4 Astrometry, Pixel scales, and Geometric Distortion
    5.4.1 Pixel Scale Time Dependence
    5.4.2 X and Y Pixel Scale Differences
    5.4.3 Geometric Distortion
    5.4.4 Drizzling
    5.4.5 Absolute Astrometry
5.5 PSF Subtraction
    5.5.1 Impact of Instrumental Effects on PSF Subtraction
5.6 Coronagraphic Reductions
    5.6.1 Data Products and File Structures
    5.6.2 Coronagraphic Acquisitions
    5.6.3 Positions of the Hole and Target
    5.6.4 Recalibrating Coronagraphic Images
    5.6.5 Reducing and Co-adding Coronagraphic Images
5.7 Analysis of Polarization Images
    5.7.1 Introduction
    5.7.2 Theory
    5.7.3 A Useful Script for Polarization Analysis
5.8 Grism Data Reduction
    5.8.1 Extraction Software
    5.8.2 Processing

This chapter describes specific tools and topics related to the analysis of NICMOS data. The first section points out some STSDAS tools for analyzing NICMOS images. The tools described here are specialized for use with NICMOS, and supplement the more general STSDAS tasks described in chapter 3 of the HST Introduction. The remainder of the chapter deals with topics of more or less general interest: photometric calibration, PSF subtraction, coronagraphic reductions, polarimetric analysis and grism data reduction.

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