ISOLWS DATA USERS MANUAL

SAI/95-219/Dc
Issue 4.0
N.Trams, ISO Science Operations Team
Using inputs from:
C.Gry, T. Lim, LWS Instrument Dedicated Team
A.Harwood, P.E.Clegg, B.Swinyard, K.King, LWS Instrument Team
S.Lord, S.Unger, IPAC.

May 9, 1997

• Contents
• List of Figures
• List of Tables
• 1 Introduction
  • 1.1 Purpose of this manual
  • 1.2 Document change history
  • 1.3 References
• 2 How to use this manual
  • 2.1 Overview of the document
  • 2.2 Where to go now
• 3 Instrument and AOT overview
  • 3.1 The LWS Instrument
  • 3.2 The LWS AOTs and operations
• 4 Instrument Characteristics
  • 4.1 Introduction
  • 4.2 Behavior of the Detector Circuit
  • 4.3 Grating Characteristics
  • 4.4 Fabry-Perot Characteristics
• 5 Calibration and Accuracy
  • 5.1 Calibration philosophy
  • 5.2 Instrument characterisation procedure
  • 5.3 Astronomical Calibration procedure
  • 5.4 Calibration sources and achieved accuracy
• 6 Data processing
  • 6.1 Processing overview
  • 6.2 Quality Check of the data
  • 6.3 Derive SPD Processing steps
  • 6.4 Auto Analysis Processing Steps
• 7 Caveats in the data processing
  • 7.1 Glitches
  • 7.2 Ramp slope order switching
  • 7.3 Last ramp in format
  • 7.4 Non-linear detector behaviour.
  • 7.5 Grating wavelength calibration
  • 7.6 Spurious features in LWS spectra.
  • 7.7 FP wavelength calibration
  • 7.8 Invalid data in FP products
  • 7.9 Correction for the LWS aperture size for point sources and extended sources
  • 7.10 Fringes in the data
  • 7.11 Straylight features in the data
  • 7.12 Differences between overlapping spectra
  • 7.13 Correction for responsivity drift
  • 7.14 Removal of the grating spectral element
• 8 Guide to instrument related data products.
  • 8.1 Inventory and naming convention
  • 8.2 Description of content and use
• 9 Getting started with LWS data
  • 9.1 How to read to data
  • 9.2 Where to find instrumental calibration parameters (SPD calibration)
  • 9.3 Where to find astronomical calibration parameters (AA calibration)
• 10 Post-processing
  • 10.1 Introduction
  • 10.2 Invalid data points in LSPD and LSAN files.
  • 10.3 Rebinning of wavelength to standard scale
  • 10.4 Co-adding repeated scans
  • 10.5 Fitting together LWS subspectra
  • 10.6 Subtraction of the astronomical background
  • 10.7 Performing absolute responsivity correction on LSNR data.
  • 10.8 Generation of maps for raster scans
• A List of acronyms