All the uu-encoded gz-compressed files were prepared with the uufiles
utility. The header of those files explains very well how to extract the
data, once the file has been saved to disk. If you are on a unix machine
these files will unpack themselves: save the file to disk, calling it,
say atlas.uu, then type: csh atlas.uu.
Uu-compressed files (ASCII, XDR, or FITS)
The format can't be any easier, this file has two columns: wavelength (Å)
and normalized flux (relative to the local continuum).
Once extracted, the Flexible Image Transport System file can be read from
IRAF or IDL (e.g. using mrdfits.pro: IDL> d=mrdfits('atlas.fits').
Note that the image has two layers, the first one contains the vector of
wavelengths (Å) and the second one the normalized flux.
Once extracted, the Flexible Image Transport System file can be read and
manipulated in IRAF very conveniently, as the dispersion has been
interpolated to a constant step, which is specified in the header. Keep
in mind that nobody has checked for a possible loss of accuracy in the
interpolation, which was done with the IRAF task rspectext.
Once extracted, the eXternal Data Representation file can be read from
IDL as follows:
IDL> openu,1,'atlas.xdr' & d=dblarr(2,122504) & readu,1,d