The Chandra Proposers' Observatory Guide
Prepared by:
Chandra X-ray Center
Chandra Project
Science, MSFC
Chandra IPI Teams
Version 10.0
December 14 2007
Contents
1.1 Program Organization
1.2 Unique Capabilities
1.3 Observatory Overview
1.4 Pointing Control and Aspect Determination (PCAD)
1.5 HRMA
1.6 Science Instrument Module (SIM)
1.6.1 Aimpoints
1.7 Ground System
1.8 Orbit
1.9 Particle Detector
1.10 ACIS
1.11 HRC
1.12 HETG
1.13 LETG
1.14 Effective Area Comparisons
1.15 Allocation of observing time
1.16 How to get information and help
2.1 Introduction
2.2 Spacecraft
2.3 Telescope System
2.4 Science Instrument Module (SIM)
2.4.1 SIM Motions
2.5 Electron Proton Helium Instrument (EPHIN)
2.6 Operations
2.6.1 Launch and On-orbit Verification
2.6.2 The Ground System
2.6.3 Commanding
2.6.4 Telemetry
2.6.5 SI Science Data
2.6.6 Event Timing and the Spacecraft Clock
2.7 Mission Planning
2.7.1 The Long-Term Schedule
2.7.2 Selecting Candidates for Short-Term Scheduling
2.7.3 The Short Term Scheduling Process
3.1 Introduction
3.2 Offset Pointing
3.3 Visibility
3.3.1 Radiation Belt Passages
3.3.2 Avoidances
3.3.3 Pitch Angle Constraints
3.4 Other Constraints and Considerations
3.4.1 Instrument Constraints and Considerations
3.4.2 User-Imposed Constraints
4.1 Introduction
4.1.1 Description and Physical Configuration
4.1.2 Sub-assembly Calibration
4.1.3 Operating Environment
4.1.4 Heritage
4.2 Calibration and Performance
4.2.1 Calibration and Model
4.2.2 HRMA Effective Area
4.2.3 Point-Spread-Function and Encircled Energy Fraction
4.3 Ghost Images
4.4 Effects of Aspect and Instrument Uncertainties
4.5 References
5.1 Introduction
5.2 Physical configuration
5.2.1 ACA
5.2.2 Fiducial lights and Fiducial Transfer System
5.2.3 IRU
5.2.4 Momentum control - RWA and MUPS
5.3 Operating principles
5.4 Performance
5.5 Heritage
5.6 Calibration
5.6.1 Pre-launch calibration
5.6.2 Orbital activation and checkout calibration
5.6.3 On-orbit calibrations
5.7 Operations
5.7.1 PCAD modes
5.7.2 Operational constraints
5.7.3 Output data
5.8 Performing an Observation
5.8.1 Star acquisition
5.8.2 Science pointing scenarios
5.8.3 PCAD capabilities (advanced)
5.9 Ground Processing
5.9.1 Data products
5.9.2 Star catalog
6.1 Introduction & Layout
6.2 Basic Principles
6.3 Optical Blocking Filter & Optical Contamination
6.4 Calibration
6.5 Quantum Efficiency and Effective Area
6.5.1 Molecular Contamination of the OBFs
6.6 Spatial Resolution & Encircled Energy
6.7 Energy Resolution
6.7.1 Correcting the Energy Resolution of the CCDs
6.8 Hot Pixels and Columns
6.9 Cosmic Ray Afterglows
6.10 Aimpoints
6.11 Dither
6.11.1 Gaps Between the CCDs
6.12 Operating Modes
6.12.1 Timed Exposure (TE) Mode
6.12.2 Alternating Exposures
6.12.3 Continuous Clocking (CC) Mode
6.13 Bias Maps
6.14 Event Grades and Telemetry Formats
6.14.1 Event Grades
6.14.2 Telemetry Formats
6.15 Pileup
6.15.1 Other Consequences of Pileup
6.15.2 Pileup Estimation
6.15.3 Reducing Pileup
6.16 On-Orbit Background
6.16.1 The Non-X-ray Background
6.16.2 The Total Background
6.16.3 Background Variability
6.16.4 Background in Continuous Clocking Mode
6.17 Sensitivity
6.18 Bright Source X-ray Photon Dose Limitations
6.19 Observing Planetary and Solar System Objects with ACIS
6.19.1 Observations with ACIS-I
6.19.2 Observations with ACIS-S
6.20 Observing with ACIS - the Input Parameters
6.20.1 Required Parameters
6.20.2 Optional Parameters
6.20.3 Non-ACIS Parameters Relevant to an Observation with ACIS
7.1 Introduction and Instrument Layout
7.2 Basic Principles
7.2.1 Aimpoints
7.3 Shutters
7.4 Dither
7.5 Spatial Resolution & Encircled Energy
7.6 Non-Dispersive Energy Resolution
7.7 Gain Variations
7.8 UV/Ion Shields
7.9 Quantum Efficiency and Effective Area
7.10 On-Orbit Background
7.10.1 HRC-I
7.10.2 HRC-S
7.10.3 Temporally Variable Background
7.11 Instrument Anomalies
7.12 Calibration
7.13 Operational considerations and constraints
7.13.1 Total Count limits
7.13.2 Count rate limits
7.14 Observing with HRC - Operating Modes
7.14.1 Timing Mode
7.14.2 Edge and Center Blanking
7.14.3 Zero-order Blocking
7.15 References
8.1 Instrument Overview
8.1.1 Examples of Observations with the HETGS
8.1.2 Scientific Objectives and Grating Heritage
8.1.3 HETGS Operating Principles
8.1.4 HETG Physical Configuration
8.2 Instrument Characteristics
8.2.1 HETGS Effective Area
8.2.2 HETGS Line Response Function
8.2.3 Background
8.2.4 Absolute Wavelength
8.3 Calibration Status
8.4 HETG Operations
8.4.1 Flight Events and Anomalies
8.4.2 Operational Constraints
8.4.3 Output Data
8.4.4 Performance Monitoring, Health and Safety
8.4.5 Thermal Response Time
8.4.6 Observation Frequency/Duty Cycle
8.4.7 Radiation Considerations
8.5 Observation Planning
8.5.1 Focal Plane Detector Considerations
8.5.2 Complications from Multiple Sources
8.5.3 Extended Sources and Spatial-Spectral Effects
8.5.4 Optimizing Detection of Isolated Emission Lines: Choice of Spectrometer
8.6 Simulations with MARX
8.7 REFERENCES
9.1 Instrument Description
9.1.1 Scientific Objectives
9.1.2 Heritage
9.1.3 Operating principles
9.1.4 Physical configuration
9.2 Calibration
9.2.1 Pre-launch Calibration
9.2.2 In Flight Calibration
9.3 LETGS Performance
9.3.1 Usage
9.3.2 Wavelength Coverage and Dispersion Relation
9.3.3 Resolving Power
9.3.4 Grating Efficiency
9.3.5 Effective Area
9.3.6 Background
9.3.7 Sample Data
9.4 Observation Planning
9.4.1 Detector Choices
9.4.2 Other Focal Plane Detector Considerations
9.4.3 General Considerations
9.5 Technical Feasibility
9.5.1 Simple Calculation of Exposure Times and Signal-to-Noise Ratio for Line and Continuum Sources
9.6 References
Appendices
A Contact Information
A.1 Contact Information
A.2 CDO Staff
B Acronym List
List of Tables
2.1 Spacecraft Parameters
3.1 Chandra observing limitations due to solar
pitch angle constraints.
(Warning: this table summarizes the limitations expected to be typical during calendar year 2008; please consult CXC web pages for updates.)
4.1 Chandra HRMA Characteristics
4.2 HRMA Encircled Energy Performance
5.1 Aspect System Requirements and Performance
5.2 PCAD modes
5.3 Default dither parameters
5.4 Aspect pipeline data products
6.1 Table of ACIS Characteristics
6.2 Nominal Optical Blocking Filter Composition and Thicknesses
6.3 Average source positions summarized in pixels (chip-x, chip-y)
6.4 Recommended SIM-Z offsets
6.5 CCD Frame Time (seconds) for Standard Subarrays
6.6 ACIS and ASCA Grades
6.7 Telemetry Saturation Limits
6.8 ASCA-Grade Distributions at 1.5keV for Different Incident Fluxes
6.9 Approximate on-orbit background counting rates
6.10 Total quiescent background rates
7.1 HRC Parameters
7.2 Current and past HRC-I calibration targets
7.3 Current and past HRC-S calibration targets
8.1 HETG(S) Parameters
8.2 Table of HETGS Gap Locations
9.1 LETGS Parameters
9.2 Planned LETGS Calibration Monitoring Observations
9.3 LETG Position-Dependent Spectral Coverage
9.4 Instrumental Absorption Edges
What's New for Cycle 10?
Please see the Call for Proposals
(http://cxc.harvard.edu/proposer/CfP/CfP_chapter1.html#T5)
list of "What's New" items for Cycle 10.
Last modified:01/22/08
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