Table of Contents COS Data Handbook List of Figures List of Tables Introduction How to Use this Handbook Handbook Structure Typographic Conventions Visual Cues Comments Chapter 1: COS Overview 1.1 Instrument Capabilities and Design FUV Spectroscopy NUV Spectroscopy Grating Offset Positions (FPPOS) NUV Imaging Data Collection Modes 1.2 COS Physical Configuration 1.2.1 The COS Detectors FUV Channel NUV Channel 1.3 Basic Instrument Operations 1.3.1 Target Acquisitions 1.3.2 Routine Wavecals 1.3.3 Typical COS Observing Sequence 1.4 COS Coordinate System Chapter 2: COS Data Files 2.1 Overview 2.2 COS File Names 2.3 COS File Structures 2.3.1 COS FITS Table Extension Files 2.3.2 COS FITS Image Extension Files 2.4 COS Data Products 2.4.1 Uncalibrated Science Data Files 2.4.2 Intermediate Science Data Files 2.4.3 Final Science Data Files (and Product Files) 2.4.4 Auxiliary Data Files Association Tables (ASN) Trailer Files (TRL) Calcos Trailer Files (TRA) Support Files (SPT) Acquisition Files (RAWACQ) Jitter Files (jit) 2-D Spacecraft Pointing Histogram (jif) 2.5 Data Storage Requirements 2.6 Headers, Keywords, and Relationship to Phase II 2.7 Error and Data Quality Array 2.7.1 Error Array 2.7.2 Data Quality Flags Chapter 3: COS Calibration 3.1 Raw Data Compilation 3.2 Pipeline Processing Overview 3.3 Calcos: Structure and Data Flow 3.4 Descriptions of Spectroscopic Calibration Steps 3.4.1 Initialization 3.4.2 BRSTCORR: Search for and Flag Bursts 3.4.3 BADTCORR: Bad Time Intervals 3.4.4 PHACORR: Pulse Height Filter 3.4.5 WALKCORR: Y-Walk Correction 3.4.6 RANDCORR: Add Pseudo-Random Numbers to Pixel Coordinates 3.4.7 TEMPCORR: Temperature-Dependent Distortion Correction 3.4.8 GEOCORR and IGEOCORR: Geometric Distortion Correction 3.4.9 DOPPCORR: Correct for Doppler Shift 3.4.10 DEADCORR: Nonlinearity Correction 3.4.11 FLATCORR: Flat-field Correction 3.4.12 WAVECORR: Wavecal Correction Determining the offsets: Applying the offsets: 3.4.13 DQICORR: Initialize Data Quality File 3.4.14 STATFLAG: Report Simple Statistics 3.4.15 X1DCORR: Locate and Extract 1-D Spectrum 3.4.16 BACKCORR: 1D Spectral Background Subtraction 3.4.17 FLUXCORR/TDSCORR: Conversion to Flux 3.4.18 HELCORR: Correction to Heliocentric Reference Frame 3.4.19 Finalization (making the sum files) 3.5 Descriptions of Imaging Calibration Steps 3.6 Customizing COS Data Calibration 3.6.1 Mechanics of Tailored Recalibration Set up the Directory Structure for Running calcos Retrieve Reference Files Edit the Calibration Header Keywords Edit the Input Association File Run Calcos 3.6.2 Using GO Wavecals 3.7 Reference Files 3.7.1 BRSTTAB: Burst Parameters Table 3.7.2 BADTTAB: Bad Time Interval Table 3.7.3 PHATAB: Pulse Height Discrimination Table 3.7.4 PHAFILE: Pulse Height Discrimination File 3.7.5 BRFTAB: Baseline Reference Frame Table 3.7.6 WALKTAB: Y Walk Correction Table 3.7.7 GEOFILE: Geometric Correction File 3.7.8 DEADTAB: Deadtime Table 3.7.9 FLATFILE: Flat-field File 3.7.10 BPIXTAB: Bad Pixel Table 3.7.11 LAMPTAB: Template Calibration Lamp Spectra Table 3.7.12 WCPTAB: Wavecal Parameter Table 3.7.13 DISPTAB: Dispersion Coefficient Table 3.7.14 XTRACTAB: 1-D Spectral Extraction Table 3.7.15 FLUXTAB: Photometric Throughput Table 3.7.16 TDSTAB: Time Dependent Sensitivity Table 3.7.17 GSAGTAB: Gain Sag Table 3.7.18 HVTAB: High Voltage Table 3.7.19 SPWCSTAB: Spectroscopic WCS Parameters Table Chapter 4: COS Error Sources 4.1 Overview 4.2 Error Sources Associated with Pipeline Processing Steps 4.2.1 FUV Dark Count Rate 4.2.2 Flat Fields NUV-MAMA Flat Fields FUV-XDL Flat Fields 4.2.3 Gain Sag 4.2.4 FUV XDL Thermal Drifts 4.3 Factors Limiting Flux and Wavelength Accuracy 4.3.1 Flux Accuracy 4.3.2 Wavelength and Spectral Resolution Accuracies Chapter 5: COS Data Analysis 5.1 Data Reduction and Analysis Applications 5.1.1 COS-Specific STSDAS Tasks 5.1.2 FITS Table Tasks 5.1.3 General Spectral Display and Analysis Tasks Plotting COS Spectral Images (flt) Plotting COS Tabular Spectra (x1d) 5.2 Evaluating Target Acquisitions and Guiding 5.2.1 Types of Target Acquisitions ACQ/SEARCH Undispersed Light (Imaging) Acquisitions (ACQ/IMAGE) Dispersed-Light Acquisitions (ACQ/PEAKD and ACQ/PEAKXD) 5.2.2 Guiding Errors for Single-Guide-Star Mode 5.3 Working with Extracted Spectra 5.3.1 Working With x1d Files in IDL 5.3.2 Working With x1d Files in Python 5.3.3 Working With x1d Files in IRAF/PyRAF Using the “Selectors Syntax” to work with 3-D tables Dumping x1d data to an ASCII File Plotting COS x1d Data 5.3.4 Redoing Spectral Extraction Correcting for Shifts Along the Dispersion Direction Adjusting the Background Subtraction 5.3.5 Splicing Extracted Spectra 5.4 Working with TIME-TAG Data 5.4.1 Displaying TIME-TAG Data in DS9 Spectroscopic Data Imaging Data TIME-TAG Animation 5.4.2 Filtering Time-Tag Data Filtering Events in the Timeline Extension Manipulating TIME-TAG Data for Variability Appendix A: COS New Spectra Position A.1 COS New Lifetime Position Appendix B: COS High Voltage B.1 COS High Voltage History
