ROSAT Processing Software and 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 currently is distributed by the U.S. ROSAT Science Data Center (RSDC).
Standard Analysis Software System (SASS) versions used to process ROSAT data are characterized as Revision 0 ("Rev0"), Revision 1 ("Rev1"), or Revision 2 ("Rev2"). SASS versions 3_0 to 5_9, which were used prior to January 27, 1993, are called Rev0; while SASS versions 6_0 through 6_9, which were used from Feb. 1993 to Jan. 1994, are called Rev1; and SASS version 7_0 and up, used after Feb. 1994, are called Rev2.
time SASS 3_0 Rev 0 U.S. FITS RODFITS || | | | (MPE) || | | | | || SASS 5_9 | | | || ------------ - - --------- - - ----------- 27 Jan 93 --------- || SASS 6_0 Rev 1 | | || | | | | || | | | | || SASS 6_9 | | | || ------------ - - --------- - - ----------- ~1 Mar 94 --------- || SASS 7_0 Rev 2 RDF >---->+<-----< RDF || | | | || | | RDF || | | | || . . . || . . . \/ . . .
The new RDF data-product format (Rationalized Data Format, introduced 1994 March) unifies the different German and U.S. FITS formats into a single set of formats. All data processed prior to 1994 January (regardless of whether processed with Rev0 or Rev1 SASS) will be re-processed using the latest Rev2 SASS software and formatted into RDF data products. Observations performed after 1993 Dec 22 will not require reprocessing, as they will be processed initially with Rev2 SASS software and formatted directly into RDF data products. Hence, all data in the public archive eventually will be replaced with Rev2-processed, RDF-formatted data products, resulting in a uniform public archive of all ROSAT observations.
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 that were part of the same sequence but that occurred in different "observing seasons" (i.e., ~6 months apart) were processed and distributed separately.
For more information about the sequence-naming conventions for each revision, select one of the following:
- U.S. Revision 0 sequence names
- U.S. Revision 1 sequence names
- Rationalized Data Format (RDF) sequence names
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Last Update: Jan 11, 1995
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