Table of Contents

Table of Contents

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Acknowledgments

Part I: Introduction

Chapter 1: Introduction

1.1 Purpose

1.1.1 Document Conventions

1.1.2 Examples Used in this Handbook

1.2 Handbook Layout

1.3 Proposal Preparations and Observations with STIS

1.3.1 The Spectrographs Group at STScI

1.4 The Help Desk at STScI

1.5 The STIS Web Pages and Support Information

1.6 Nonproprietary STIS Data

Chapter 2: Special Considerations for Cycle 14

2.1 STIS Unlikely to be Available During Cycle 14

2.2 HST Two-Gyro Science Mode

2.3 New versions of STIS Exposure Time Calculators

Differences and improvements with respect to CGI ETCs

Significant changes since the Phase I version of the APT Spectroscopic ETC

2.4 Use of Available-but-unsupported Capabilities

2.5 Scheduling Efficiency and Visit Orbit Limits

2.6 MAMA Scheduling Policies

2.7 Prime and Parallel Observing: MAMA Bright Object Constraints

2.8 STIS Snapshot Policies

Chapter 3: Introduction to STIS

3.1 Instrument Capabilities

3.2 Instrument Design

3.2.1 Detectors

3.2.2 STIS Physical Configuration

3.3 Basic Instrument Operations

3.3.1 Typical STIS Observing Sequence

3.4 Designing STIS Observations

3.4.1 Identify Science Requirements and Define STIS Configuration

3.4.2 Determine Exposure Time and Check Feasibility

3.4.3 Identify Need for Non-Science Exposures and Constraints

3.4.4 Determine Total Orbit Request

Part II: User's Guide

Chapter 4: Spectroscopy

4.1 Overview

4.1.1 Throughputs

4.1.2 STIS vs. ACS Spectroscopy

4.1.3 Limiting Magnitudes

4.1.4 Saturation

4.1.5 MAMA Bright-Object Limits

4.1.6 Scanned Gratings: Prime and Secondary (Tilt) Positions

4.1.7 Cross-Over Regions

4.2 First-Order Long-Slit Spectroscopy

4.2.1 Gratings for First-Order Spectroscopy

4.2.2 Slits for First-Order Spectroscopy

4.2.3 STIS Pseudo-aperture Positions

4.2.4 Detailed First-Order Spectroscopic Information

4.3 Echelle Spectroscopy in the Ultraviolet

4.3.1 Echelle Gratings

4.3.2 Slits for Echelle Spectroscopy

4.3.3 Detailed Echelle Information

4.4 Objective-Prism Spectroscopy

Chapter 5: Imaging

5.1 Imaging Overview

5.1.1 STIS versus ACS Imaging

5.1.2 STIS vs. WFPC2 Imaging

5.1.3 Caveats for STIS Imaging

5.1.4 Throughputs and Limiting Magnitudes

5.1.5 Signal-To-Noise Ratios

5.1.6 Saturation

5.2 Optical CCD Imaging

5.2.1 Effect of the optical baffles on STIS CCD imaging

5.2.2 Unfiltered (Clear) CCD Imaging-50CCD

5.2.3 Optical Longpass-F28X50LP

5.2.4 [O III]-F28X50OIII

5.2.5 [O II]-F28X50OII

5.3 Ultraviolet Imaging with the MAMA Detectors

5.3.1 Bright-Object Limits

5.3.2 Optical Performance

5.3.3 Unfiltered (Clear) MAMA Imaging-25MAMA

5.3.4 Longpass-Filtered MAMA Imaging- F25SRF2 and F25QTZ

5.3.5 MAMA Narrow-band-Filtered Imaging

5.4 Neutral-Density Filters

Chapter 6: Exposure Time Calculations

6.1 Overview

6.1.1 The STIS Exposure Time Calculators

6.2 Determining Count Rates from Sensitivities

6.2.1 Spectroscopy

6.2.2 Imaging

6.3 Throughput and Sensitivity

6.4 Computing Exposure Times

6.4.1 Calculating Exposure Times for a Given Signal-to-Noise

6.5 Detector and Sky Backgrounds

6.5.1 Detector Backgrounds

6.5.2 Sky Background

6.6 Tabular Sky Backgrounds

6.7 Extinction Correction

6.8 Exposure Time Examples

6.8.1 Spectroscopy of Diffuse Source (M86)

6.8.2 Spectroscopy of Solar-Analog Star P041-C

6.8.3 Extended Source with Flux in cgs units (NGC 6543): Imaging and Spectroscopy

6.8.4 Echelle Spectroscopy of a Bright Star with Large Extinction (Sk -69° 215)

6.8.5 Imaging a Faint Stellar Source

6.8.6 Time-Tag Observations of a Flare Star (AU Mic)

Chapter 7: Feasibility and Detector Performance

7.1 The CCD

7.1.1 Detector Properties

7.1.2 Effects of the Change to STIS Side-2 Electronics on CCD Performance

7.1.3 CCD Spectral Response

7.1.4 CCD Sensitivity

7.1.5 CCD Long-Wavelength Fringing

7.1.6 Fringing due to the Order Sorter Filters

7.1.7 Optical Performance

7.1.8 Readout Format

7.1.9 Analog-to-Digital Conversion: Selecting the CCDGAIN

7.2 CCD Operation and Feasibility Considerations

7.2.1 CCD Saturation

7.2.2 CCD Shutter Effects

7.2.3 Cosmic Rays

7.2.4 Hot Pixels

7.2.5 CCD Bias Subtraction and Amplifier Non-Linearity

7.2.6 Charge Transfer Efficiency

7.2.7 Mitigation of CTE Loss for Long-slit Spectroscopy

7.2.8 UV Light and the STIS CCD

7.3 The MAMA Detectors

7.3.1 MAMA Properties

7.3.2 MAMA Spectral Response

7.3.3 MAMA Sensitivity

7.3.4 Optical Performance

7.4 MAMA Operation and Feasibility Considerations

7.4.1 MAMA Saturation-Overflowing the 16 Bit Buffer

7.4.2 MAMA Darks

7.4.3 MAMA Signal-to-Noise Ratio Limitations

7.4.4 MAMA Non-linearity

7.5 MAMA Spectral Offsetting

7.6 MAMA Bright-Object Limits

7.6.1 Overview

7.6.2 Observational Limits

7.6.3 How Do You Determine if You Violate a Bright Object Limit?

7.6.4 Policy and Observers' Responsibility in Phase I and Phase II

7.6.5 Policy on Observations That Fail Because they Exceed Bright-Object Limits

7.6.6 What To Do If Your Source is Too Bright for Your Chosen Configuration?

7.6.7 Bright-Object Protection for Solar System Observations

7.6.8 Jupiter and Saturn

Chapter 8: Target Acquisition

8.1 Introduction

8.1.1 Initial Pointing

8.1.2 Acquisitions

8.1.3 Peakups

8.1.4 Drift Rates

8.2 STIS Onboard CCD Target Acquisitions (ACQ)

8.2.1 How it Works

8.2.2 Target-Location Algorithms

8.2.3 Selecting Target Acquisition Parameters

8.2.4 Specifying Acquisitions in Phase II

8.2.5 Solar-System Acquisitions

8.3 Onboard Target Acquisition Peakups (ACQ/PEAK)

8.3.1 Selecting Peakup Parameters

8.3.2 Specifying Acquisition Peakups in Phase II

8.4 Determining the PLATE-ID of HST Observations

8.5 Acquisition Examples

8.5.1 Point source Acquisition of an Isolated Object

8.5.2 Point Source Acquisition of Bright, Isolated Object with CCD Dispersed Light Peakup

8.5.3 Diffuse-Source Acquisition of a Spiral Galaxy

8.5.4 Point Source Acquisition in a Crowded Field

8.5.5 Point Source Acquisition of a QSO with Fuzz Behind the Fiduciary Bar

8.5.6 Point Source Acquisition of a Bright, Isolated Star Into the Wedge

8.6 STIS Post-Observation Target Acquisition Analysis

8.6.1 Paper Products-Coarse Centering

8.6.2 TAS-Fine Centering

8.6.3 Did the Acquisition Succeed?

Chapter 9: Overheads and Orbit-Time Determination

9.1 Overview

9.2 STIS Exposure Overheads

9.3 Orbit Use Determination Examples

9.3.1 Sample Orbit Calculation 1: Long-Slit Spectroscopy of the Galaxy M86

9.3.2 Sample Orbit Calculation 2: Low-Dispersion Spectroscopy of Solar-Analog Star P041-C

9.3.3 Sample Orbit Calculation 3: Imaging and Spectroscopy of the Cat's Eye Planetary Nebula, NGC 6543

9.3.4 Sample Orbit Calculation 4: MAMA Echelle Spectroscopic Exposures in the CVZ

9.3.5 Sample Orbit Calculation 5: Faint CCD Imaging

Chapter 10: Summary and Checklist

10.1 Phase I Proposing

10.1.1 Phase I Orbit-Allocation Examples

10.2 Phase II-Scheduling Approved Observations

Part III: Supporting Material

Chapter 11: Data Taking

11.1 Basic Operating Modes

11.1.1 CCD ACCUM Mode

11.1.2 MAMA ACCUM Mode

11.1.3 MAMA TIME-TAG Mode

11.2 Exposure Sequences and Contemporaneous Calibrations

11.2.1 Auto-Wavecals

11.2.2 CR-SPLIT

11.2.3 Fringe Flat Fields

11.2.4 Repeat Exposures

11.3 Patterns and Dithering

11.3.1 STIS Imaging Patterns

11.3.2 STIS Spectroscopic Patterns

11.3.3 Generic Patterns

11.3.4 Combining Patterns

11.3.5 Dither Strategies

11.4 Fixing Orientation on the Sky

Chapter 12: Special Uses of STIS

12.1 Slitless First-Order Spectroscopy

12.2 Long-Slit Echelle Spectroscopy

12.3 Time-Resolved Observations

12.4 Observing Too-Bright Objects with STIS

12.5 High Signal-to-Noise Ratio Observations

12.5.1 Dithering

12.5.2 FP-SPLIT Slits for Echelle Observations

12.6 Improving the Sampling of the Line-Spread Function

12.7 Considerations for Observing Planetary Targets

12.7.1 Long-Slit Spectroscopy

12.8 Parallel Observing with STIS

12.8.1 Using STIS in Parallel with Other Instruments

12.8.2 The STIS Archival Pure Parallel Program

12.9 Coronagraphic Spectroscopy

12.10 Coronagraphic Imaging-50CORON

Chapter 13: Spectroscopic Reference Material

13.1 Introduction

13.2 Using the Information in this Chapter

13.2.1 Wavelength Ranges

13.2.2 Grating Sensitivities and Throughputs

13.2.3 Signal-To-Noise Plots

13.2.4 Plate Scales

13.2.5 Apertures

13.2.6 Fiducials on Bars

13.2.7 Spatial Profiles

13.2.8 Line-Spread Functions (Instrumental Profiles)

13.3 Gratings

13.4 Apertures

13.5 Spatial Profiles

13.6 Line-Spread Functions

13.7 Spectral Purity, Order Confusion, and Peculiarities

13.7.1 Recommendations for stellar observations with narrow slits

13.7.2 Order Overlap and Scattered Light for Echelle Gratings

13.7.3 Spectroscopic Mode Peculiarities

13.7.4 Railroad Tracks

13.8 MAMA Spectroscopic Bright-Object Limits

Chapter 14: Imaging Reference Material

14.1 Introduction

14.2 Using the Information in this Chapter

14.2.1 Sensitivity Units and Conversions

14.2.2 Signal-To-Noise

14.2.3 Point Spread Functions

14.3 CCD

14.4 NUV MAMA

14.5 FUV MAMA

14.6 Image-Mode Geometric Distortion

14.7 Spatial Dependence of the STIS PSF

14.8 MAMA Imaging Bright Object Limits

Part IV: Calibration

Chapter 15: Overview of Pipeline Calibration

15.1 Pipeline Processing Overview

15.2 How Phase II parameter choices affect calibration

15.3 More Detailed Information

Chapter 16: Accuracies

16.1 Summary of Accuracies

16.1.1 Flats

Chapter 17: Calibration Status and Plans

17.1 Introduction

17.2 Ground Testing and Calibration

17.3 SMOV2 Testing and Calibration

17.4 Cycle 7 Calibration

17.4.1 Calibration Priorities

17.4.2 Calibration Status

17.5 Cycle 8 Calibration

17.6 Cycle 9 Calibration

17.7 Cycle 10 Calibration

17.8 Cycle 11 Calibration

17.9 Cycle 12 Calibration

17.10 Cycle 13 Calibration

Appendix A: Available-But-Unsupported Spectroscopic Capabilities

A.1 Introduction

A.2 Full Aperture Complement

A.3 Central Wavelength Settings

Glossary

Index