The ftp directory contains parts of two observations of the Crab
supernova remnant performed by the BeppoSAX instruments during the
Science Verification Phase.

Detailed information on BeppoSAX data reduction and analysis software
is available at:


FOT directory
Data in the "fot" directory are in original FOT format
(see the page 


for more information).
They are divided in 4 subdirectories:

op_839_fot_624_saxdas     PDS & HPGSPC SAXDAS naming convention
op_839_fot_624_xas        PDS & HPGSPC XAS naming convention
op_886_fot_491_saxdas     LECS & MECS  SAXDAS naming convention
op_886_fot_491_xas        LECS & MECS  XAS naming convention

XAS users should copy the files with the XAS naming convention.
SAXDAS users should copy the files with the SAXDAS naming convention.

For the Wide Field Camera (WFC) instrument, two observations are supplied:

wfc_op_917w12_fot.tar.gz    op_917/wfc1, /wfc2 (CRAB + Galactic Centre)
wfc_op_919_test_dat.readme  op_919/wfc1, helpfile and data in *.dat files

For details about the WFC analysis software see SAX/SDC Web pages on WFC software at

FITS directory
The "fits" directory contains SAXDAS linearized and screened event files
(*lev*flt.fits files).
These are equivalent to ROSAT or ASCA linearized event
files and can be directly analyzed with popular X-ray analysis packages.
The "fits" directory also contains SAXDAS fits housekeeping files,
containing housekeeping, LECS ratemeters, attitude and auxiliary 
quantities data (*hkg* files) and MECS ratemeters files (*eng* files)
Data contained in these files can be plotted and used to form
new GTI using the SAXDAS program hkplot (see the page

  /bepposax/software/saxdas/hkplot_walk.html for more information).

Please note that the abrupt changes in the LECS Crab countrate are caused by
source obscuration by the window support strongback grid. The grid
consists of 4 by 4 arcminute squares, and can cause extra, energy
dependent, obscuration of up to ~30% for a point source. The effect of
this obscuration is accounted for in the LECS response matrix
generation program (LEMAT).

For the WFCs, a tar is available containing the corresponding fits files
for op_917/wfc1, /wfc2 (wfc_op_917w12_fits.tar.gz) and op_919/w1 
(wfc_op_919_test_fits.tar.gz). The tarfile for op_917 contains
*0000*.gti good time interval files, in which the earth occultation 
periods (with earth rim angle > 28 from centre of Field of view) are
already excluded. 
For an explanation see the SAX/SDC Web page with the walk-through WFC 
basic data analysis at 


Problems, reports or any question can be addressed to