NICMOS Instrument Handbook for Cycle 11

Table of Contents

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Acknowledgments

NICMOS Instrument Team

Table of Contents

Part I: Introduction

Chapter 1: Introduction and General Considerations

Purpose

Document Conventions

Layout

NICMOS Proposal Preparation

The Help Desk at STScI

The NICMOS Instrument Team at STScI

Supporting Information and the NICMOS Web Site

NICMOS History in Brief

Changes Relative to Cycles 7 and 7N

Recommendations for Proposers

Supported and Unsupported NICMOS Capabilities

Chapter 2: Overview of NICMOS

Instrument Capabilities

History of NICMOS

NICMOS Instrument Design

Physical Layout

Imaging Layout

Camera NIC1

Camera NIC2

Camera NIC3

Location and Orientation of Cameras

The NICMOS Cooling System

Basic Operations

Detectors' Characteristics and Operations

Comparison to CCDs

Target Acquisition Modes

Attached Parallels

Chapter 3: Designing NICMOS Observations

The Visual Target Tuner (VTT)

Part II: User's Guide

Chapter 4: Imaging

Filters & Optical Elements

Nomenclature

Out-of-Band Leaks in NICMOS Filters

Photometry

Solar Analog Absolute Standards

White Dwarf Absolute Standards

Photometric throughput and stability

Intrapixel sensitivity variations

Special Situations

Sources with Extreme Colors

Extended Sources with Extreme Spatial Color Variations

Creating Color-dependent Flat Fields

Focus History

Image Quality

Strehl Ratios

NIC1 and NIC2

Vignetting in NIC1 and NIC2

NIC3

Vignetting in NIC3

PSF Structure

Optical aberrations: coma and astigmatism

Field Dependence of the PSF

Temporal Dependence of the PSF: HST Breathing and Cold Mask Shifts

Cosmic Rays

Photon and Cosmic Ray Persistence

The Infrared Background

The "Pedestal Effect"

Chapter 5: Coronagraphy, Polarimetry and Grism Spectroscopy

Coronagraphy

Coronagraphic Acquisitions

Onboard Acquisition (Mode-2 Acquisition)

Reuse Target Offset (RTO) and Interactive Acquisitions

PSF Centering

Temporal Variations of the PSF

FGS Guiding

Cosmic Ray Persistence

Contemporary Flat Fields

Coronagraphic Decision Chart

Polarimetry

NIC 1 and NIC2 Polarimetric Characteristics and Sensitivity

Ghost images

Observing Strategy Considerations

Limiting Factors

Limiting Polarization

Position Angle of Incoming Polarization Relative to NICMOS Orientation

Polarimetry Decision Chart

Grism Spectroscopy

Multi-Object Spectroscopy

Grism Calibration

Relationship Between Wavelength and Pixel

Sensitivity

Intrapixel Sensitivity

Grism Decision Chart

Chapter 6: NICMOS Apertures and Orientation

NICMOS Aperture Definitions

NICMOS Coordinate System Conventions

Orients

Chapter 7: NICMOS Detectors

Detector basics

Detector Characteristics

Overview

Dark current

The "bump"

Flat fields and the DQE

Read Noise

Linearity and Saturation

Detector Artifacts

Shading

Amplifier Glow

Overexposure of NICMOS Detectors

Electronic bars and bands

Bad Pixels

"Grot"

Chapter 8: Detector Readout Modes

Introduction

Detector Resetting as a Shutter

Accumulate Mode

Multiple Initial and Final Sample Readout

Read Times and Dark Current Calibration in ACCUM Mode

Multiple-Accumulate Mode

MULTIACCUM Predefined Sample Sequences (SAMP-SEQ)

Trade-offs Between ACCUM and MULTIACCUM

Acquisition Mode

Part III: How to Plan an Observation

Chapter 9: Exposure Time Calculations

Overview

Instrumental Factors

Detectors

Optics

Background Radiation

Calculating NICMOS Imaging Sensitivities

Signal to noise Calculation

Saturation and Detector Limitations

Exposure Time Calculation

WWW Access to the Exposure Time Calculator

Chapter 10: Overheads and Orbit Time Determination

Overview

NICMOS Exposure Overheads

Orbit Use Determination

Observations in the Thermal Regime Using a Chop Pattern and MULTIACCUM

Coronagraphic Overhead Example

Chapter 11: Techniques for Dithering, Background Measurement and Mosaicing

Introduction

Strategies For Background Subtraction

Compact Objects

Extended Objects

Chopping and Dithering Patterns

Note on Orientation:

Move the sky or the telescope?

Dither Patterns

Chop Patterns

Combined Patterns

Map Patterns

Examples

Phase II Proposal Instructions for Patterns

Types of Motions

Part IV:Calibration Overview

Chapter 12: Calibration Pipeline

Overview

Associations

Concept

Usage

Re-engineering

NICMOS Pipeline

Static Calibrations-calnica

Contemporaneous Observations-calnicb

NICMOS Data Products

Standard NICMOS Dataset Structure

Science Image (SCI)

Error Array (ERR)

Data Quality Flags Array (DQ)

Samples Array (SAMP)

Integration Time Array (TIME)

IRAF Access

On-The-Fly-Reprocessing (OTFR)

Chapter 13: Calibration Goals and Plans

Expected Calibration Accuracies

Remarks

Areas of Significant Uncertainty

Provisional Cycle 11 Calibration Goals

Calibration Plans

Calibration Outsourcing

Special Calibrations

Part V: Appendices

Appendix 1: Imaging Reference Material

Camera 1, Filter F090M

Camera 1, Filter F095N

Camera 1, Filter F097N

Camera 1, Filter F108N

Camera 1, Filter F110M

Camera 1, Filter F110W

Camera 1, Filter F113N

Camera 1, Filter F140W

Camera 1, Filter F145M

Camera 1, Filter F160W

Camera 1, Filter F164N

Camera 1, Filter F165M

Camera 1, Filter F166N

Camera 1, Filter F170M

Camera 1, Filter F187N

Camera 1, Filter F190N

Camera 1, Polarizer POL0S

Camera 2, Filter F110W

Camera 2, Filter F160W

Camera 2, Filter F165M

Camera 2, Filter F171M

Camera 2, Filter F180M

Camera 2, Filter F187N

Camera 2, Filter F187W

Camera 2, Filter F190N

Camera 2, Filter F204M

Camera 2, Filter F205W

Camera 2, Filter F207M

Camera 2, Filter F212N

Camera 2, Filter F215N

Camera 2, Filter F216N

Camera 2, Filter F222M

Camera 2, Filter F237M

Camera 2, Polarizer POL0L

Camera 3, Filter F108N

Camera 3, Filter F110W

Camera 3, Filter F113N

Camera 3, Filter F150W

Camera 3, Filter F160W

Camera 3, Filter F164N

Camera 3, Filter F166N

Camera 3, Filter F175W

Camera 3, Filter F187N

Camera 3, Filter F190N

Camera 3, Filter F196N

Camera 3, Filter F200N

Camera 3, Filter F212N

Camera 3, Filter F215N

Camera 3, Filter F222M

Camera 3, Filter F240M

Appendix 2: Flux Units and Line Lists

Infrared Flux Units

Some History

Units for NICMOS and Available Software

Formulae

Converting Between Fn and Fl

Conversion Between Fluxes and Magnitudes

Conversion Between Surface Brightness Units

Look-up Tables

Examples

Infrared Line Lists

Appendix 3: Bright Object Mode

Bright Object Mode

Glossary and Acronym List

Index