Next: 2.3 Basic processing steps Up: 2. Processing SWS Data Previous: 2.1 Introduction

2.2 Reading the data from CD-ROM

Users should either read the relevant data (e.g. AAR or SPD files) from the CD-ROM to their diskspace and work on it from there, or read it from the CD-ROM straight into their data reduction software.

2.2.0.1 IDL

To read a the FITS files in using the IDL ASTRON library:

data = readfits( <file.fits>, header, exten_no = 1 )

reads in a data array. If <file.fits> was an AAR file then the array `data' would have a size of 52 * length of SWAA file + header.

print, tbget( header, data, 1, 0)

for an AAR would print the first wavelength.

print, tbget( header, data, 1, 1)

for an AAR would print the second wavelength.

print, tbget( header, data, 2, 1012)

for an AAR would print the 1013th flux.

The header variable will tell you in what order variables appear in the data array. For AAR the order, given in section 9.4.1, is:

'SWAAWAVE'
'SWAAFLUX'
'SWAASTDV'
'SWAATINT'
'SWAADETN'
'SWAAITK '
'SWAAUTK '
'SWAARPID'
'SWAASPAR'
'SWAALINE'
'SWAASDIR'
'SWAASCNT'
'SWAASTAT'
'SWAAFLAG'

2.2.0.2 MIDAS

For MIDAS users the commands:

indisk/fits <file.fits> file
print/tab file file.dat

will output the fits file as plain ASCII which can then be imported into most packages (thanks to Paul Crowther of UCL).

Next: 2.3 Basic processing steps Up: 2. Processing SWS Data Previous: 2.1 Introduction

SWS Instrument & Data Manual, Issue 1.0, SAI/98-095/Dc