Contents

• Contents
• List of Figures
• List of Tables
• 1. Introduction
  • 1.1 Purpose
  • 1.2 Structure
  • 1.3 How to Contact Us
  • 1.4 ISOPHOT Publications
    • 1.4.1 Acknowledgements and guidelines
    • 1.4.2 Inventory of publications
• 2. Instrument Description
  • 2.1 Introduction
  • 2.2 Overview
  • 2.3 Focal Plane Scale
  • 2.4 Data Collection with ISOPHOT
    • 2.4.1 Signal flow in ISOPHOT
    • 2.4.2 Cold Readout Electronics (CRE)
    • 2.4.3 Detector Interface Electronics (DIE)
    • 2.4.4 Readout timing control
  • 2.5 ISOPHOT Measurement Concept
  • 2.6 Detector Subsystems
    • 2.6.1 PHT-P
    • 2.6.2 PHT-C
    • 2.6.3 PHT-S
  • 2.7 Fine Calibration Sources (FCSs)
  • 2.8 Focal Plane Chopper (FPC)
  • 2.9 Filters
• 3. Instrument Modes and Astronomical Observation Templates
  • 3.1 Chopping
  • 3.2 Single-Pointing Multi-Filter and Multi-Aperture Modes
  • 3.3 Raster Mode
  • 3.4 Absolute Photometry
  • 3.5 Oversampled Linear Scans and Maps
  • 3.6 Sparse Maps
  • 3.7 Spectrophotometry
  • 3.8 Polarimetry
  • 3.9 Serendipity Mode
  • 3.10 ISOPHOT Modes of Operation
    • 3.10.1 PHT-P: PHT03, PHT04, PHT05, PHT17/18/19
    • 3.10.2 PHT-C: PHT22, PHT25, PHT32, PHT37/38/39
    • 3.10.3 PHT-S: PHT40
    • 3.10.4 Polarisation observations: PHT50, PHT51
• 4. Instrumental Characteristics
  • 4.1 Overview
  • 4.2 Detector Properties
    • 4.2.1 Detector responsivity
    • 4.2.2 Signal non-linearities
    • 4.2.3 Transient behaviour after flux change
    • 4.2.4 Drift behaviour of responsivity
    • 4.2.5 Curing procedures
    • 4.2.6 Dark signal and noise
    • 4.2.7 Detector flat-fields
    • 4.2.8 Detector saturation
  • 4.3 Features due to Electronics
    • 4.3.1 Anomalous first readouts on a ramp
    • 4.3.2 CRE (ramp) linearity
    • 4.3.3 Signal dependence on reset interval
    • 4.3.4 Detector bias: de-biasing effects
    • 4.3.5 Readout saturation
    • 4.3.6 Disturbances by chopper commanding
    • 4.3.7 CRE latch-up
  • 4.4 Effects of Ionising Radiation
  • 4.5 Optical Performance
    • 4.5.1 Instrumental footprint on the sky
    • 4.5.2 Point source intensity fractions
    • 4.5.3 Chopper vignetting/offset
    • 4.5.4 Inhomogeneous FCS illumination
  • 4.6 Spectral Performance
    • 4.6.1 PHT-S instrumental line profile
    • 4.6.2 PHT-S wavelength calibration
  • 4.7 Straylight
    • 4.7.1 Straylight during FCS calibrations
    • 4.7.2 Instrumental straylight
    • 4.7.3 Spectral straylight
  • 4.8 Instrumental Polarisation
  • 4.9 Backgrounds
    • 4.9.1 Confusion due to diffuse galactic emission
    • 4.9.2 Confusion by galaxies
    • 4.9.3 Zodiacal light
  • 4.10 Global Instrument Data
• 5. Photometric Calibration
  • 5.1 Overview
  • 5.2 Calibration Strategy
    • 5.2.1 Calibration involving the FCS
    • 5.2.2 Non-linear detector responsivity
    • 5.2.3 Signal correction for chopped observations with PHT-P and -C
    • 5.2.4 Absolute calibration of FCS
    • 5.2.5 Photometry with PHT-P and PHT-C
    • 5.2.6 Spectro-photometry with PHT-S
  • 5.3 Point Sources Versus Extended Sources
  • 5.4 Aperture Calibration
  • 5.5 PHT-S Wavelength Calibration
  • 5.6 Photometric Calibration in AOTs
    • 5.6.1 General signal derivation
    • 5.6.2 Multi-filter photometry: PHT03 and PHT22
    • 5.6.3 Mapping: PHT03, PHT22, PHT32
    • 5.6.4 Sparse maps: PHT17/18/19 and PHT37/38/39
    • 5.6.5 Multi-aperture photometry: PHT04
    • 5.6.6 Absolute photometry: PHT05 and PHT25
    • 5.6.7 PHT-S: PHT40
  • 5.7 Calibration Files
    • 5.7.1 Calibration-G files
    • 5.7.2 Calibration-A files
• 6. Data Processing Level: Derive_ERD
• 7. Data Processing Level: Derive_SPD
  • 7.1 Overview
  • 7.2 Ramp Processing
    • 7.2.1 Discarding destructive readouts
    • 7.2.2 Discarding disturbed non-destructive readouts
    • 7.2.3 Discarding data with OTF or OPF `off'
    • 7.2.4 Data identification and separation
    • 7.2.5 Determine chopper position and step number
    • 7.2.6 Conversion of digitised numbers to CRE output voltages
    • 7.2.7 Discarding saturated readouts
    • 7.2.8 Correction for non-linearities of the integration ramps
    • 7.2.9 Ramp deglitching
    • 7.2.10 Extraction of the signals and their uncertainties
  • 7.3 Signal Processing: Staring PHT-P and PHT-C
    • 7.3.1 Reset interval correction
    • 7.3.2 Dark signal subtraction
    • 7.3.3 Correction for non-linear detector response of PHT-P and PHT-C
    • 7.3.4 Signal deglitching
    • 7.3.5 Transient correction
    • 7.3.6 Averaging signals of same instrument set-up
    • 7.3.7 Obtaining the median of all photo-currents
    • 7.3.8 Ramp statistics in SPD and Cal-A headers
  • 7.4 Signal Processing: Staring PHT-S
    • 7.4.1 Dark signal subtraction
    • 7.4.2 Transient correction and calibration of signals
    • 7.4.3 Computation of the weighted mean flux
  • 7.5 Signal Processing: Chopped PHT-P and PHT-C
    • 7.5.1 Processing overview for chopped observations
    • 7.5.2 Setting up data for generic pattern construction
    • 7.5.3 Generic pattern construction
    • 7.5.4 Determination of source signal
    • 7.5.5 Correction for chopped signal loss: Sky measurement
    • 7.5.6 Correction for chopped signal loss: FCS measurement
  • 7.6 Signal Processing: Chopped PHT-S
    • 7.6.1 Obtaining the average signal per chopper plateau
    • 7.6.2 Separation of source and background signal
    • 7.6.3 Determine the signals averaged over a measurement
    • 7.6.4 Spectral response function corrected for chopped signal losses
    • 7.6.5 Determination of source and background spectrum
  • 7.7 Signal Processing: PHT32 Raster Maps
    • 7.7.1 Obtaining the average signal per chopper plateau
    • 7.7.2 Correction for chopper vignetting
  • 7.8 Signal Processing: PHT-S Raster Maps
    • 7.8.1 Obtaining the average signal per raster point
    • 7.8.2 Determination of the spectrum per raster point
  • 7.9 Signal Processing: PHT04 Staring Multi-Aperture Photometry
    • 7.9.1 Sorting out eligible PHT04 observations
    • 7.9.2 Analysis of the background subtracted source signal
    • 7.9.3 Summary of SPD warning messages for PHT04
  • 7.10 In-band Power Calibration
    • 7.10.1 Default responsivities
    • 7.10.2 Determination of in-band power from FCS measurement
    • 7.10.3 Signal to in-band power conversion for P detectors
    • 7.10.4 Signal to in-band power conversion for C detectors
    • 7.10.5 In-band power for PHT-P and PHT-C chopped observations
    • 7.10.6 In-band power for raster and sparse maps
    • 7.10.7 Dependencies on mission dates
  • 7.11 Ancillary SPD Data
    • 7.11.1 FCS measurements
    • 7.11.2 PHT-S dark measurement
    • 7.11.3 Dark signal measurement
    • 7.11.4 FCS straylight measurement
  • 7.12 Quality Flags for SPD Records
• 8. Data Processing Level: Derive_AAR
  • 8.1 Overview
  • 8.2 PHT Auto Analysis Processing Per AOT
    • 8.2.1 PHT03
    • 8.2.2 PHT04
    • 8.2.3 PHT05
    • 8.2.4 PHT17/18/19
    • 8.2.5 PHT22
    • 8.2.6 PHT25
    • 8.2.7 PHT32
    • 8.2.8 PHT37/38/39
    • 8.2.9 PHT40
  • 8.3 Common Processing Steps
    • 8.3.1 Read SPD header
    • 8.3.2 Read SPD record
    • 8.3.3 Determine celestial coordinates of each pixel in record
    • 8.3.4 Determination of the equatorial offsets of the detector centre
  • 8.4 Photometry
    • 8.4.1 Determine source in-band power for chopped observations
    • 8.4.2 Summation of the in-band powers over all PHT-C detector pixels
    • 8.4.3 Fit two-dimensional Gaussian to point sources in the C-arrays
    • 8.4.4 Interpolate missing pixels
    • 8.4.5 Determination of Gaussian parameters
    • 8.4.6 Photometry with PHT-P and PHT-C
    • 8.4.7 Surface brightness determination for PHT-P and PHT-C
    • 8.4.8 Write PHT-P point source photometry product
    • 8.4.9 Write PHT-P extended source photometry product
    • 8.4.10 Write PHT-C point source photometry product
    • 8.4.11 Write PHT-C extended source photometry product
  • 8.5 Mapping
    • 8.5.1 Statistical flat-field correction for C100 and C200
    • 8.5.2 Establish image pixel size
    • 8.5.3 Establish maximum image size
    • 8.5.4 Determination of the coverage by a sky sample in the image
    • 8.5.5 Binning sky samples onto image pixels
    • 8.5.6 Write image products
    • 8.5.7 Write PHT-P raster scan photometry products
    • 8.5.8 Write PHT-C raster scan photometry products
  • 8.6 Spectroscopy with PHT40
    • 8.6.1 PHT-S spectrum in wavelength units for point sources
    • 8.6.2 PHT-S spectrum for extended sources
    • 8.6.3 Write spectroscopy products
• 9. Photometric Calibration Accuracies
  • 9.1 Overview
  • 9.2 Calibration Accuracies per Detector
  • 9.3 Status of Scientific Validation of PHT AOTs
• 10. Caveats
  • 10.1 Overview
  • 10.2 Caveat on this Document
  • 10.3 Error Calculation and Propagation
  • 10.4 Validity Ranges of FCS Calibration Files
  • 10.5 Inhomogeneous FCS Illumination of PHT-P Apertures
  • 10.6 Non-Geometric Aperture Beam Size Scaling
  • 10.7 Detector Signal Transients
  • 10.8 Long Term Detector Drifts
  • 10.9 Limitations in Use of PHT Colour Correction Factors
  • 10.10 Non-Linearity of Detector Responsivity with Flux
  • 10.11 Incomplete Looking Raster Maps
  • 10.12 Point Spread Function Fraction Factors in the Data Products
  • 10.13 Residual Flat-Field Structures in PHT22 Raster Maps
  • 10.14 Point Source Photometry from Mini-Maps
  • 10.15 Filters with Less Reliable Photometry
  • 10.16 PHT-S Dynamic Spectral Response Calibration
  • 10.17 PHT-S Pointings Not Centred in the Aperture
• 11. Getting Started with ISOPHOT Data
  • 11.1 Obtaining ISOPHOT Data
  • 11.2 First Look at the Products
  • 11.3 Further Processing
• 12. Guide to Data Products
  • 12.1 Quick Reference: Synopsis of all ISOPHOT Products
    • 12.1.1 ERD products
    • 12.1.2 SPD products
    • 12.1.3 AAR products
    • 12.1.4 Cal-G products: Derive_SPD
    • 12.1.5 Cal-G products: Derive_AAR
    • 12.1.6 Cal-G products: auxillary
  • 12.2 Product Types Sorted by AOT
• 13. Products Description
  • 13.1 Overview
  • 13.2 ERD Product Types
    • 13.2.1 Rationale behind product design
    • 13.2.2 Product PPER
    • 13.2.3 Product P1ER
    • 13.2.4 Product P2ER
    • 13.2.5 Product P2ES
    • 13.2.6 Product PSER
    • 13.2.7 Product PSTA
  • 13.3 SPD Product Types
    • 13.3.1 Rationale behind product design
    • 13.3.2 Product PPxS
    • 13.3.3 Product PC1S
    • 13.3.4 Product PC2S
    • 13.3.5 Product PSSS
    • 13.3.6 Product PSLS
    • 13.3.7 Product PPxA
    • 13.3.8 Product PCxA
    • 13.3.9 Product PSSD
    • 13.3.10 Product PSLD
    • 13.3.11 Product PPxD
    • 13.3.12 Product PC1D
    • 13.3.13 Product PC2D
    • 13.3.14 Pixel status flag
  • 13.4 AAR Product Types
    • 13.4.1 Rationale behind product design
    • 13.4.2 Product PPAP
    • 13.4.3 Product PPAE
    • 13.4.4 Product PCAP
    • 13.4.5 Product PCAE
    • 13.4.6 Product PGAI
    • 13.4.7 Product PGAU
    • 13.4.8 Product PGAT
    • 13.4.9 Product PPAS
    • 13.4.10 Product PCAS
    • 13.4.11 Product PSAP
    • 13.4.12 Product PLAP
    • 13.4.13 Product PSAE
    • 13.4.14 Product PLAE
    • 13.4.15 Product PSAS
    • 13.4.16 Product PLAS
• 14. Calibration-G Products
  • 14.1 Overview
  • 14.2 Observation Time Dependent Calibration
    • 14.2.1 Product PTIMEDEP: PHT calibration time dependency
  • 14.3 DIE Power Calibration
    • 14.3.1 Product PDIE1TRANS: PHT DIE1 power calibration table
    • 14.3.2 Product PDIE2TRANS: PHT DIE2 power calibration table
  • 14.4 Selection of Readouts
    • 14.4.1 Product PSELNDR: PHT non-destructive readout selection
  • 14.5 CRE Linearisation Corrections
    • 14.5.1 Product PPCRELIN: linearisations for P1, P2, and P3
    • 14.5.2 Product PC1CRELIN: linearisations for C100
    • 14.5.3 Product PC2CRELIN: linearisations for C200
  • 14.6 Signal Correction for Reset Interval
    • 14.6.1 Product PP1RESETI: parameters for conversion to 1/4s reset interval for P1
    • 14.6.2 Product PP2RESETI: parameters for conversion to 1/4s reset interval for P2
    • 14.6.3 Product PP3RESETI: parameters for conversion to 1/4s reset interval for P3
    • 14.6.4 Product PC1RESETI: parameters for conversion to 1/4s reset interval for C100
    • 14.6.5 Product PC2RESETI: parameters for conversion to 1/4s reset interval for C200
  • 14.7 Detector Dark Signals
    • 14.7.1 Product PSDARK: PHT-S dark signals
    • 14.7.2 Product PPDARK: dark signals for detectors P1, P2, and P3
    • 14.7.3 Product PC1DARK: dark signals for detector C100
    • 14.7.4 Product PC2DARK: dark signals for detector C200
  • 14.8 Correction for Signal Non-Linearity
    • 14.8.1 Product PP1SLINR: signal linearisation for PHT-P1
    • 14.8.2 Product PP2SLINR: signal PHT-P2 linearisation
    • 14.8.3 Product PP3SLINR: signal linearisation for PHT-P3
    • 14.8.4 Product PC1SLINR: signal linearisation for PHT-C100
    • 14.8.5 Product PC2SLINR: signal linearisation for PHT-C200
  • 14.9 PHT-S Dynamic Calibration for Staring Observations
    • 14.9.1 Product PSDYNAMIC: PHT-S dynamic calibration - flux correction
    • 14.9.2 Product PSDYNWT: PHT-S dynamic calibration - weighting function
  • 14.10 Correction for Signal Losses in Chopped Mode
    • 14.10.1 Product PP1CHOPSIG: PHT-P1 chopped signal correction
    • 14.10.2 Product PP2CHOPSIG: PHT-P2 chopped signal correction
    • 14.10.3 Product PP3CHOPSIG: PHT-P3 chopped signal correction
    • 14.10.4 Product PC1CHOPSIG: PHT-C100 chopped signal correction
    • 14.10.5 Product PC2CHOPSIG: PHT-C200 chopped signal correction
  • 14.11 Vignetting Corrections
    • 14.11.1 Product PP1VIGN: vignetting corrections for P1
    • 14.11.2 Product PP2VIGN: vignetting corrections for P2
    • 14.11.3 Product PP3VIGN: vignetting corrections for P3
    • 14.11.4 Product PC1VIGN: vignetting corrections for C100
    • 14.11.5 Product PC2VIGN: vignetting corrections for C200
  • 14.12 FCS Power Calibration
    • 14.12.1 Product PP1FCSPOW: PHT-P1 FCS power calibration table
    • 14.12.2 Product PP2FCSPOW: PHT-P2 FCS power calibration table
    • 14.12.3 Product PP3FCSPOW_01/02: PHT-P3 FCS power calibration table
    • 14.12.4 Product PC1FCSPOW_01/02: PHT-C100 FCS power calibration table
    • 14.12.5 Product PC2FCSPOW_01/02: PHT-C200 FCS power calibration table
  • 14.13 PHT-P and PHT-C Default Responsivities
    • 14.13.1 Product PPRESP_01/02: PHT default responsivities for P1, P2 and P3 detectors
    • 14.13.2 Product PC1RESP_01/02: PHT default responsivities for the C100 detector
    • 14.13.3 Product PC2RESP_01/02: PHT default responsivities for the C200 detector
  • 14.14 Array Illumination by FCS
    • 14.14.1 Product PC1ILLUM_01/02: FCS illumination correction for C100
    • 14.14.2 Product PC2ILLUM_01/02: FCS illumination correction for C200
  • 14.15 Inhomogeneous FCS illumination of PHT-P
    • 14.15.1 Product PP1FCSAP: FCS aperture correction tables for P1
    • 14.15.2 Product PP2FCSAP: FCS aperture correction tables for P2
    • 14.15.3 Product PP3FCSAP: FCS aperture correction tables for P3
  • 14.16 PHT-P Filter-to-Filter Corrections
    • 14.16.1 Product PPFTOF: PHT-P filter-to-filter correction
  • 14.17 Wavelength Dependent Detector Flat-Fields
    • 14.17.1 Product PC1FLAT: PHT C100 filter-to-filter flat-field correction
    • 14.17.2 Product PC2FLAT: PHT C200 filter-to-filter flat-field correction
  • 14.18 Point Spread Function Corrections
    • 14.18.1 Product PPPSF: PHT-P point spread function corrections
    • 14.18.2 Product PCPSF: PHT-C point spread function corrections
  • 14.19 PHT-S Wavelength and Signal Calibration
    • 14.19.1 Product PSPECAL: PHT-S wavelength and signal calibration
  • 14.20 Conversion from Power on Detector to Flux Density
    • 14.20.1 Product PFLUXCONV: PHT-P/C power calibration
    • 14.20.2 Product PFLUXCONV: PHT-P/C reference wavelengths
  • 14.21 Effective Solid Angles of Apertures and Pixels
    • 14.21.1 Product PPOMEGA: aperture dimensions and solid angles for P1, P2, and P3
    • 14.21.2 Product PC1OMEGA: dimensions and solid angles for C100 pixels
    • 14.21.3 Product PC2OMEGA: dimensions and solid angles for C200 pixels
  • 14.22 Colour Corrections
    • 14.22.1 Product PCCBB: black body colour correction
    • 14.22.2 Product PCCMBBONE: modified black body colour correction
    • 14.22.3 Product PCCMBBTWO: modified black body colour correction
    • 14.22.4 Product PCCPOWER: Power-law colour correction
  • 14.23 Footprint Matrices for PHT-P and C
    • 14.23.1 Product PP2FOOTP: PHT-P2 footprint matrices
    • 14.23.2 Product PP3FOOTP: PHT-P3 footprint matrices
    • 14.23.3 Product PC1FOOTP: PHT-C100 footprint matrices
    • 14.23.4 Product PC2FOOTP: PHT-C200 footprint matrices
  • 14.24 Relative System Responses
    • 14.24.1 Product PPFILTRAN: PHT-P relative system response
    • 14.24.2 Product PCFILTRAN: PHT-C relative system response
• A. Instrument Tables
  • A.1 Mean Filter/Aperture Specifications
    • A.1.1 PHT-P filters
    • A.1.2 PHT-P apertures
    • A.1.3 PHT-C filters
    • A.1.4 Other filterwheel components
  • A.2 Filter Transmission Data
• B. Conversion Algorithms for ERD
  • B.1 Temperature Sensors
  • B.2 Selected FCS Power
  • B.3 Focal Plane Chopper Deflection
  • B.4 Description of the Pixel Status Flag PIXF in ERD Products
• C. Colour Corrections
  • C.1 Application of Tabulated Colour Correction Factors
  • C.2 Computation of Colour Correction Factors
    • C.2.1 Derivation of flux density values from in-band power values
    • C.2.2 Flux density conversion factors for different spectral energy distributions
    • C.2.3 Derivation of colour correction factors from flux density conversion factors
  • C.3 Colour Correction Values
• D. Magnitude System in ISOPHOT
• E. List of Acronyms
• F. List of Symbols
  • F.1 Roman Symbols
  • F.2 Greek Symbols
• G. Glossary
• Bibliography
• Index