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Rosat status report #76

			ROSAT Status Report #76
			    Dec 15th 1993

ROSAT Sequence-naming Conventions

As ROSAT data processing software has been upgraded during the course of the
mission, the sequence-naming conventions have evolved.  The following is a
summary of these conventions.  Note that the term "U.S. FITS" refers to the
FITS format that is currently distributed by the U.S. ROSAT Science Data
Center (RSDC).

The versions of the Standard Analysis Software System (SASS) used to process
ROSAT data have been categorized as either Revision 0 ("Rev0") or Revision 1
("Rev1").  SASS versions 3_0 to 5_9, which were used prior to January 27,
1993, are called Rev0, while SASS versions 6_0 and higher (running since
January 27, 1993) are called Rev1.

A key difference between data processed during Rev0 and those processed
during Rev1 pertains to the way separate observation intervals (called
"OBIs") are combined.  During Rev0, all available OBIs were used to produce
a single set of data products.  On the other hand, during Rev1, OBIs which
were part of the same sequence but which occurred in different "observing
seasons" (i.e., ~6 months apart) were processed and distributed separately.

A further distinction exists between "processing" and "REprocessing".  In
order to make the entire ROSAT data stream available as Rev1 data products
(in RDF format - cf.  section 3 below), observations whose data were
previously processed only with Rev0 SASS will be reprocessed (beginning in
early 1994) to provide Rev1 data products.  (Note that observations
processed for the first time using Rev1 SASS to generate RDF data products
will not require reprocessing.)

The following diagram illustrates this situation:

time     SASS 3_0                       U.S. FITS           RODFITS    
 ||          |                              |                (MPE)     
 ||          |                              |                  |       
 ||      SASS 5_9         REV 0             |                  |       
 ||    ------------ - - --------- - - ----------- 27 Jan 93 ---------
 ||      SASS 6_0         REV 1             |                  |       
 ||          |                              |                  |       
 ||          |                              |                  |       
 ||    - SASS 6_9 - - - - - - - - - - ----------- ~1 Jan 94 ---------
 ||          |                               \               /
 ||          |                                \             /
 ||          |                                 \           /
 ||          .                                  \         /
 ||          .                                   \       /              
 ||          .                          - - - - - \ - - / - - - - - -
 \/          .                                      RDF

1. U.S. Revision 0 names

The following naming conventions apply to all data processed by the U.S.
RSDC using SASS versions 3_0 through 5_9 (Rev0) and distributed in the U.S.
FITS format.  As stated above, during Rev0 all available OBIs were used to
produce a single set of data products, regardless of whether or not they
occurred in different "observing seasons".

Rev0 file names are of the form:


where:         r                - stands for ROSAT

               <detector-code>  - code for detector/filter:
                                        h - HRI
                                        p - PSPC
                                        f - Filtered PSPC.

               <ROR>           - 6-digit Rosat Observation Request number

              <extensions>     - additional characters specifying "type" 
                                  of data.

For example, the photon event files produced by IRAF/PROS from Rev0 data
products might be:

        rp123456.qp  - PSPC observations (.qp is the IRAF "qpoe" extension)
        rp234567f.qp - PSPC Filter observations  
        rh345678.qp  - HRI observations

2. U.S. Revision 1 names

The following naming conventions apply to all data processed by the U.S.
RSDC using the SASS versions 6_0 and greater (Rev1) and distributed in the
U.S. FITS format, i.e., data products produced after January 27, 1993.

During Rev1 processing, observations conducted over different "observing
seasons" (i.e., over gaps of several months) are no longer combined to form
a single data set.  Additional observations, known as "add-ons", are
processed separately.  The sequence-naming convention for Rev1 (U.S. FITS)
file names is as follows:


where the two additional digits added after the ROR number are:

                <add-on#>       - 00 indicates the first segment,
                                - 01 indicates the second segment,
                                - 02 indicates the third segment, 
                                    and so on.

For example, Rev1 IRAF/PROS "qpoe" file names might be:

         rp12345600.qp - PSPC observations
         rf23456700.qp - PSPC filtered observations
         rh34567800.qp - HRI observations

3. Rationalized Data Format names

A new data-product format, RDF (Rationalized Data Format; expected to be
introduced in January 1994), will unify the German and U.S. FITS formats
used previously into a single set of formats, necessitating a further change
in naming conventions.  All U.S. data processed prior to January 1994
(regardless of whether processed with Rev0 or Rev1 SASS) will be REprocessed
using the latest Rev1 software in order to produce RDF FITS data products
for the public data archive.

An additional identifier has been inserted into the RDF file names to
indicate both "split" Rev0 sequences and "mispointed" observations (those
for which the telescope was not pointed at the intended target).  The RDF
FITS file names have the form:


where <obs-code> has replaced <add-on#>:

  <obs-code> = 

        n00          - observed as scheduled, first segment ("n" = Normal)

        a01,a02,...  - observed as scheduled: first, second, and subsequent
                       segments added to the "normal" segment ("a" = Add-on)

        a00,a01,...  - indicate 1st, 2nd, and subsequent segments for an
                       observation which was first processed as a single 
                       observation in rev 0 processing.

        m01,m02,...  - mispointed segment (targeting was not as scheduled),
                       numbering begins at 1 ("m" = Mispointed)

In this case, the IRAF/PROS name for RDF-format "qpoe" files might be:

        rp123456n00.qp - PSPC observations
        rf234567n00.qp - PSPC filtered observations
        rh345678n00.qp - HRI observations

Status of Validation and Verification of the ROSAT Data.

The process of preparing detailed Validation and Verification (V&V)
Reports for ROSAT data before delivery to GOs was terminated in
mid-October (1993) due to RSDC project funding cuts.  In its place,
however, (in mid-November) we instituted an automated check of
important data files for all observations.  Reports for data sets
processed between the above two dates (for which the GOs did not
receive a V&V report) are available on request from the SAO-RSDC
(email request to: rsdc@cfa.harvard.edu).

The automated V&V process generates a single-page report and, if
relevant, a comparison of key parameters (such as exposure times,
background rates, and number of detected sources) between the current
and the previous processing of the same data set.  The check also
includes a search for missing files and verification that the
RDF-format FITS files translate into IRAF without errors.  The
existence of a V&V report thus ensures that the data are all present
and readable by IRAF/PROS.