Preface
How to Use
this Handbook xvii

Handbook Structure xvii

Handbook Updates xix

Typographic Conventions xx

Visual Cues xx

Keystrokes xx

Comments xx

Introduction to HST Data 21

Chapter 1
Getting HST Data 1-1

Archive Overview 1-1

Accessing the Archive 1-2

Registering to Retrieve Hubble Data 1-3

Authorization to Retrieve Proprietary Data 1-3

Archive Documentation and Help 1-3

Getting Your Data Quickly 1-4

Getting Data with StarView 1-4

Welcome Screen 1-5

Command Usage and Screen Interaction 1-5

Searching the Catalog 1-6

Retrieving Datasets From the Archive 1-12

Exiting StarView 1-17

Transferring Your Data with FTP 1-17

Running StarView via Remote Access 1-18

Identifying Calibration Reference Files 1-19

Reading HST Data Tapes 1-22

Loading Packages 1-22

Mounting the Tape 1-23

Setting File Format 1-23

Using strfits 1-23

Chapter 2
HST File Formats 2-1

Historical Perspective 2-2

FITS File Format 2-3

Working with FITS Image Extensions 2-4

Working with FITS Table Extensions 2-7

GEIS File Format 2-10

Converting FITS to GEIS 2-11

GEIS Data Groups 2-11

Working with GEIS Files 2-11

Chapter 3
STSDAS Basics 3-1

Navigating STSDAS 3-1

STSDAS Structure 3-2

Packages of General Interest 3-2

Displaying HST Images 3-4

The display Task 3-4

Working with Image Sections 3-7

Analyzing HST Images 3-8

Basic Astrometry 3-9

Examining and Manipulating Image Data 3-10

Working with STIS and NICMOS Imsets 3-12

Photometry 3-15

Displaying HST Spectra 3-17

FOS and GHRS Spectra 3-17

STIS Spectra 3-18

Producing Hardcopy 3-19

Analyzing HST Spectra 3-21

Preparing FOS and GHRS Data 3-21

Preparing STIS Spectra for Analysis 3-23

General Tasks for Spectra 3-25

STSDAS fitting Package 3-29

specfit 3-32

References 3-32

Available from STScI 3-32

Available from NOAO 3-32

Other References Cited in This Chapter 3-33

FOC 35

Chapter 4
FOC Instrument
Overview 4-1

Spatial Resolution and PSF 4-2

Filters 4-4

Formats & Fields of View 4-4

Sensitivity 4-5

Polarization & Spectroscopy 4-6

What to Expect 4-7

Chapter 5
FOC Data Structures 5-1

File Suffixes 5-1

Header Keywords 5-2

Relationship to Proposed Observations 5-7

Paper Products 5-10

Chapter 6
FOC Calibration 6-1

FOC Pipeline Processing 6-1

FOC Calibration Switches 6-2

Dezooming of Zoomed Images (PIXCORR) 6-2

Absolute Sensitivity Correction (WAVCORR) 6-3

Geometric Correction (GEOCORR) 6-5

Flatfield Correction (UNICORR) 6-7

Reasons to Recalibrate 6-8

Absolute Sensitivity Keywords 6-8

Flatfields 6-9

Geometric Correction Files 6-9

Improved Pipeline Algorithms 6-10

User Calibrations 6-10

How to Recalibrate 6-10

Chapter 7
FOC
Error Sources 7-1

Overview of FOC Characteristics 7-1

Nonlinearity 7-2

Geometric Correction 7-4

Flatfield Residuals 7-5

Border Effects 7-5

Video and Digitizing Defects 7-7

Reseau Marks, Scratches, and Blemishes 7-8

Pattern Noise 7-8

Large Scale Variations 7-9

Time Variability 7-9

Format-Dependent Effects 7-9

Format-Dependent Sensitivity 7-10

Background 7-11

Detector Background 7-11

Geocoronal Emission Lines 7-12

Zodiacal Light and Diffuse Galactic Background 7-12

Scattered Stray Light 7-12

Filter Induced Image Shifts 7-13

Errors in Absolute Photometry (f/96) 7-14

Absolute Sensitivity of the f/48 Detector 7-15

Chapter 8
FOC Data Analysis 8-1

Photometry 8-1

Point Spread Function 8-2

Photometric Accuracy 8-3

Astrometry 8-6

Polarimetry 8-7

Objective-Prism Spectroscopy 8-10

Long-Slit Spectroscopy 8-14

Tribulations of the f/48 Spectrograph 8-15

Reduction of f/48 Spectra 8-16

Accuracy of f/48 Spectroscopy 8-16

Summary of FOC Accuracies 8-17

FGS 19

Chapter 9
FGS Overview 9-1

FGS Capabilities 9-2

FGS Design 9-3

FGS Optics 9-3

FGS Aperture 9-6

S-curves 9-8

FGS 1R 9-13

FGS Control 9-15

Target Acquisition and Tracking 9-16

Search 9-17

CoarseTrack 9-17

FineLock 9-18

Transfer Scans 9-21

FGS Guiding 9-21

FGS Astrometry 9-22

Astrometry with FGS 3 9-23

Chapter 10
FGS Data Structures 10-1

Engineering Telemetry Data 10-1

FGS Astrometry Files 10-2

Relationship to Phase II Request 10-6

Jitter Files 10-6

SMS Support Data 10-7

Chapter 11
FGS Calibration 11-1

The Visit 11-1

Initial Data Processing 11-2

POSITION Mode Pipeline 11-3

Position Mode Observations 11-3

Processing Individual Observations 11-4

Assembling the Visit 11-5

TRANSFER Mode Pipeline 11-7

TRANSFER Mode Dataset 11-7

Mapping TRANSFER Mode to POSITION Mode 11-7

Limitations of the TRANSFER Mode Pipeline 11-8

POSITION Mode Pipeline Output 11-8

Chapter 12
FGS Error Sources 12-1

Levels of POSITION Mode Errors 12-1

Observation-Level POSITION Errors 12-2

Rotation Angle Errors 12-2

Centroiding Errors 12-2

Locating Interferometric Null 12-5

Optical Field Angle Distortion 12-7

Lateral Color Error 12-8

Cross Filter Effect 12-9

Differential Velocity Aberration 12-10

Lever Arm Length and Offset Angle 12-10

Visit-Level POSITION Errors 12-11

POSITION Mode De-jittering Errors 12-11

Drift Correction Errors 12-12

Field-Level POSITION Errors 12-13

TRANSFER Mode Errors 12-14

Chapter 13
FGS Data Analysis 13-1

Analyzing Individual Observations 13-1

Plate Overlays 13-3

Resolving Structure with TRANSFER Mode 13-5

FGS Response to a Binary 13-6

TRANSFER Mode Data Reduction 13-9

Uncertainties in TRANSFER Mode Data 13-10

NICMOS 15

Chapter 14
NICMOS Instrument
Overview 14-1

Instrument Overview 14-1

Detector Readout Modes 14-2

MULTIACCUM 14-3

ACCUM 14-4

BRIGHTOBJ 14-4

RAMP 14-5

Chapter 15
NICMOS Data
Structures 15-1

NICMOS Data Files 15-1

File Name Suffixes 15-2

Science Data Files 15-3

Auxiliary Data Files 15-9

Header Keywords 15-10

Working with NICMOS Files 15-15

From the Phase II Proposal to Your Data 15-21

Paper Products 15-22

Chapter 16
NICMOS Calibration 16-1

Pipeline Processing 16-1

NICMOS Calibration Software 16-2

The Calibration Pipeline 16-2

Grism Spectroscopy 16-3

Basic Data Reduction: calnica 16-3

Mosaicing: Calnicb 16-10

Input Files 16-11

Output Files 16-12

Processing 16-13

Grism Data Reduction: Calnicc 16-16

Input Files 16-16

Output Files 16-16

Processing 16-18

Recalibration 16-21

Why Recalibrate? 16-21

Recalibrating the Data 16-22

Calculating Absolute Sensitivity 16-24

Chapter 17
NICMOS
Error Sources 17-1

Flatfield Errors 17-1

Thermal-Vacuum versus On-Orbit Flatfields 17-1

Characteristics and Uncertainties of Flatfields 17-2

Color Dependence of Flatfields 17-6

Dark Current Subtraction Errors 17-7

Dark Current Pedestal 17-7

Synthetic MULTIACCUM Darks 17-8

Uncertainties in the Synthetic Darks 17-10

Instrument Artifacts 17-11

Non-Zero Zeroth Read Correction for Bright Sources 17-11

Effects of Overexposure and the "Mr. Staypuft" Anomaly 17-11

Vignetting 17-12

Amplifier Glow 17-12

Intra-Pixel Sensitivity Variations 17-13

Hot Pixels, Cold Pixels, and Grot 17-13

Cosmic Rays 17-14

Calibration Goals 17-14

Chapter 18
NICMOS Data
Analysis 18-1

STSDAS Software 18-1

Photometric Calibrations 18-2

Units for NICMOS Photometry 18-3

Fluxes and Magnitude Zeropoints 18-3

Photometric Corrections 18-4

Magnitudes and Photometric Systems Transformations 18-8

Absolute Photometry for Emission Line Filters 18-9

Absolute Spectrophotometry with NICMOS Grisms 18-10

PSF Subtraction 18-11

Analysis of Polarization Images 18-12

Introduction 18-12

Theory 18-13

A Useful Script for Polarization Analysis 18-14

STIS 17

Chapter 19
STIS Overview 19-1

Instrument Capabilities and Design 19-1

Basic Instrument Operations 19-4

Chapter 20
STIS Data Structures 20-1

Overview 20-1

STIS File Structures 20-2

STIS FITS Image Extension Files 20-2

Tabular Storage of STIS Data 20-5

Types of STIS Files 20-6

Understanding Associations 20-6

Headers, Keywords, and Relationship to Phase II 20-9

Error and Data Quality Arrays 20-13

The Error Array 20-14

Data Quality Flagging 20-14

STIS Paper Products 20-15

Chapter 21
STIS Calibration 21-1

Pipeline Processing Overview 21-1

Structure of calstis 21-3

Data Flow Through calstis 21-9

Descriptions of Calibration Steps 21-15

Recalibration of STIS Data 21-29

Mechanics of Full Recalibration 21-30

Rerunning Subsets of the Calibration Pipeline 21-33

Updates to calstis 21-35

Chapter 22
STIS Error Sources 22-1

Calibration Goals 22-1

Calibration Accuracy Resources 22-3

Factors Limiting Flux and Wavelength Accuracy 22-5

Flux Accuracy 22-5

Wavelength and Spatial Accuracies 22-6

Chapter 23
STIS Data Analysis 23-1

Data Reduction Applications 23-1

STIS-Specific Reduction and Analysis Tasks 23-2

Working with Two Dimensional Extracted Spectra 23-3

Sensitivity Units and Conversions 23-3

Wavelength and Spatial Information 23-5

TIME-TAG Data 23-6

Target Acquisition Data 23-8

WFPC2 13

Chapter 24
WFPC2 Instrument
Overview 24-1

Chapter 25
WFPC2 Data Structures 25-1

Data Files and Suffixes 25-1

Header Keywords 25-3

Correlating Phase II Exposures with Data Files 25-8

WFPC2 Paper Products 25-10

Chapter 26
WFPC2 Calibration 26-1

Overview of Pipeline Calibration 26-3

Standard Pipeline Calibration 26-5

Calibration Files 26-6

Calibration Steps 26-7

Recalibration 26-10

Why and When to Recalibrate 26-10

Assembling the Calibration Files 26-13

Setting Calibration Switches 26-13

Post-Pipeline Calibration 26-15

Warm Pixels 26-16

Removing Cosmic Rays from Co-aligned Images 26-20

Charge Traps 26-22

Chapter 27
WFPC2
Error Sources 27-1

Bias Subtraction Error 27-2

Flatfield Correction Errors 27-2

Dark Current Subtraction Errors 27-3

Electronic Dark Current 27-3

Dark Glow 27-4

Image Anomalies 27-5

Bias Jumps 27-5

Residual Images 27-6

PC1 Stray Light 27-10

Other Anomalies 27-11

Chapter 28
WFPC2 Data Analysis 28-1

Photometric Zero Point 28-2

Photometric Systems Used for WFPC2 Data 28-2

Determining the Zero Point 28-4

Photometric Corrections 28-6

Time-Dependent Corrections 28-6

Position-Dependent Corrections 28-11

Other Photometric Corrections 28-13

An Example of Photometry with WFPC2 28-15

Polarimetry 28-16

Astrometry 28-18

Dithering 28-19

Accuracy of WFPC2 Results 28-23

References 28-25

Appendixes 27

Appendix A
IRAF Primer A-1

Initiating IRAF A-1

Setting Up IRAF A-2

Starting and Stopping an IRAF Session A-3

IRAF Basics A-4

Loading Packages A-4

Running Tasks A-5

Getting Help A-6

Setting Parameters A-8

Setting Environment Variables A-10

File Management A-11

Troubleshooting A-13

Getting IRAF and STSDAS A-13

Retrieving the IRAF and STSDAS Software A-14

Getting the Synphot Database A-15

Extracting the synphot Unix Tar Files A-15

Appendix B
HST File Names B-1

Appendix C
Observation
Logs C-1

Observation Log Files C-1

Retrieving Observation Logs C-8

Using Observation Logs C-9

Guiding Mode C-9

Guide Star Acquisition Failure C-10

Moving Targets and Spatial Scans C-11

High Jitter C-11

Appendix E
Resources on the
Internet E-1

Glossary F-1