8.1 Retrieving and Reading the Data

LWS data, as any other ISO data, can be retrieved from the ISO Data Archive (IDA) at the following address:

         http://www.iso.vilspa.esa.es/ $\rightarrow$ Access the Archive

We refer to the ISO Handbook Volume I, [21] for more information on the ISO Data Archive and how to use it.

The ISO data files obtained can either be general, applying to all instruments e.g. satellite pointing, housekeeping etc., or instrument specific. A full description of the general file types are also given in the ISO Handbook Volume I, [21], along with a description of the data layout for each of these files. The LWS specific files are fully described in Chapter 7 in the present handbook volume.

A recommendation for new users is to request the data files using the default 'basic science' retrieval option. This option allows an observer to retrieve a basic set of files for the requested observation although it is expected that most users will only require the final LSAN product file (see Section 7.2.7).
However, for most options of the LWS Interactive Software (LIA), the user will need to retrieve the data at SPD level.

All ISO product files are in FITS format and almost all, including all LWS specific product files, have the data stored in a FITS binary extension.
They can be read for example with the `mrdfits' command in IDL.
The following is an example to read wavelength and flux in the file lsan63901302.fits:

new=mrdfits('lsan63901302.fits',1,h1)
wavelength=new.lsanwav
flux=new.lsanflx