Wide Field and Planetary Camera 2 Instrument Handbook

Table of Contents

---

Acknowledgments

Chapter 1: Introduction

1.1 Instrument Overview

1.1.1 Field-of-View

1.1.2 Spectral Filters

1.1.3 Quantum Efficiency and Exposure Limits

1.1.4 CCD Detector Technology

1.1.5 UV Imaging

1.1.6 Aberration Correction and Optical Alignment

1.2 Comparison of WFPC2, ACS, NICMOS, and STIS

1.2.1 Comparison of WFPC2 and ACS

1.2.2 Comparison of WFPC2 and NICMOS

1.2.3 Comparison of WFPC2 and STIS

1.3 History of WFPC2

1.4 The Previous vs. Current Generation: WF/PC-1 vs. WFPC2

1.5 Organization of this Handbook

1.6 The Help Desk at STScI

1.7 Further Information

Chapter 2: Instrument Description

2.1 Science Objectives

2.2 WFPC2 Configuration, Field-of-View, and Resolution

2.3 Overall Instrument Description

2.4 Quantum Efficiency

2.5 Shutter

2.6 Serial Clocks

2.7 Overhead Times

2.8 CCD Orientation and Readout

2.9 Calibration Channel

Chapter 3: Optical Filters

3.1 Introduction

3.2 Choice of Broad Band Filters

3.3 Linear Ramp Filters

3.3.1 Spectral Response

3.3.2 Target Locations

3.3.3 LRF Photometric Calibration

3.4 Redshifted [OII] Quad Filters

3.5 Polarizer Quad Filter

3.5.1 Polarization Calibration

3.6 Methane Quad Filter

3.7 Wood's Filters

3.8 Red Leaks in UV Filters

3.9 Apertures

Chapter 4: CCD Performance

4.1 Introduction

4.2 Quantum Efficiency

4.3 Dynamic Range

4.4 Read Noise and Gain Settings

4.5 Bright Object Artifacts

4.5.1 Blooming

4.5.2 Horizontal Smearing

4.5.3 Diffraction Effects and Ghost Images

4.6 Residual Image

4.7 Flat Field Response

4.8 Dark Backgrounds

4.8.1 Sources of Dark Current

4.8.2 Dark Current Evolution

4.8.3 Darktime

4.9 Cosmic Rays

4.10 SAA and Scheduling System Issues

4.11 Radiation Damage and Hot Pixels

4.12 Photometric Anomalies: CTE and "Long vs. Short"

4.12.1 CTE Trends and Causes

4.12.2 Photometric Effects of the CTE Anomaly

4.12.3 Physical Effects of the CTE Anomaly

4.12.4 Mitigating CTE During Observations

4.12.5 Final Characterization of the CTE Anomaly

4.12.6 The Long vs. Short Anomaly

4.13 WF4 CCD Anomaly

Chapter 5: Point Spread Function

5.1 Effects of OTA Spherical Aberration

5.2 Aberration Correction

5.3 Wavefront Quality

5.4 CCD Pixel Response Function

5.5 Model PSFs

5.6 PSF Variations with Field Position

5.6.1 Aperture Corrections vs. Field Position

5.7 PSF Variations with Time / OTA Focus

5.8 PSF Anomaly in F1042M Filter

5.9 Large Angle Scattering

5.10 Ghost Images

5.11 Optical Distortion

5.11.1 Pixel Area Correction

5.11.2 34th-Row Defect

5.11.3 Geometric Distortion Closeout Calibrations

Chapter 6: System Throughput and SNR / Exposure Time Estimation

6.1 System Throughput

6.2 On-Line Exposure Time Calculator

6.3 Target Count Rates

6.3.1 Count Rates for Stellar Sources

6.3.2 Count Rates for Power Law Sources

6.3.3 Count Rates for Emission Line Sources

6.4 Sky Background

6.5 Signal-to-Noise Ratio Estimation

6.5.1 Point Sources -- PSF Fitting

6.5.2 Point Sources -- Aperture Photometry

6.5.3 Extended Sources

6.6 Exposure Time Estimation

6.7 Sample SNR Calculations

6.7.1 Point Sources

6.7.2 Extended Sources

6.7.3 Emission Line Sources

6.8 Photometric Anomalies

6.9 Red Leaks in UV Filters

6.10 Long-term Photometric Stability

6.11 Short-term Time Dependence of UV Response

Chapter 7: Observation Strategies

7.1 Observing Faint Targets

7.2 Observing Bright Targets

7.3 Observing Faint Targets Near Bright Objects

7.4 Cosmic Rays

7.5 Choice of Exposure Times

7.6 Dithering with WFPC2

7.6.1 Dither Strategies

7.6.2 Analysis of Dithered Data

7.7 Pointing Accuracy

7.7.1 Absolute Pointing Accuracy

7.7.2 Updates to Aperture / Coordinate Systems

7.7.3 Pointing Repeatability

7.7.4 Tracking Modes

7.8 CCD Position and Orientation on Sky

7.8.1 ORIENT Anomaly

7.9 Polarization Observations

7.10 Observing with Linear Ramp Filters

7.11 Emission Line Observations of Galaxy Nuclei

Chapter 8: Calibration and Data Reduction

8.1 Calibration Observations and Reference Data

8.2 Flat Fields

8.3 Dark Frames

8.4 Bias Frames

8.5 Data Products and Data Reduction

8.6 Pipeline Processing

8.7 On-The-Fly and Static Archive Systems

8.8 Fluxes and Standard Magnitudes

8.9 Color Transformations of Primary Filters

8.10 Calibration Plan Summary

8.11 Outsourced Calibration Programs

8.12 Calibration Accuracy

References

Appendix A: Passband Plots

A.1 Filter Passbands, with and w/out Total System

A.1.1 F122M, F130LP, F160BW

A.1.2 F165LP, F170W, F185W

A.1.3 F218W, F255W, F300W

A.1.4 F336W, F343N, F375N

A.1.5 F380W, F390N, F410M

A.1.6 F437N, F439W, F450W

A.1.7 F467M, F469N, F487N

A.1.8 F502N, F547M, F555W

A.1.9 F569W, F588N, F606W

A.1.10 F622W, F631N, F656N

A.1.11 F658N, F673N, F675W

A.1.12 F702W, F785LP, F791W

A.1.13 F814W, F850LP, F953N

A.1.14 F1042M, FQUVN-A, FQUVN-B

A.1.15 FQUVN-C, FQUVN-D, FQCH4N-A

A.1.16 FQCH4N15-B, FQCH4N33-B, FQCH4N-C

A.1.17 FQCH4N-D, Parallel and Perpendicular Polarizers

A.2 Normalized Passbands including System Response

Appendix B: Point Source SNR Plots

Acronyms

Index