Since the end of 1992 a public ROSAT Data Archive (RDA) for the X-ray data is maintained at both the German RSDC (MPE) and the US RSDC (GSFC) in identical form. An additional copy of the RDA is installed at the UKRDAC (UL).
The RDA contains processed data sets of all pointed ROSAT XRT observations for which the original data rights of the principal investigator have expired. The data are a subset of those initially delivered to the PI and comprise primary and secondary data products necessary for detailed data analysis. Not included are the result files of the Standard Analysis Processing, since the initial processing was not regarded as sufficiently reliable for general unscreened usage (see appendix H in connection with the ROSAT Result Archive).
Data sets are all in FITS format. The initial FITS implementations in Germany and the USA were different. From the beginning of the reprocessing of all pointed observations, data sets are now delivered in a new common FITS format, the Rationalized Data Format (RDF; developed by GSFC). Until the reprocessing is complete -- expected in the second half of 1995 -- the archive user will therefore find ROSAT XRT data in 3 different FITS structures and with slightly varying contents. This is usually not a problem because the analysis systems of the RSDCs can handle all three formats and the most important data sets (photon event, attitude, orbit and housekeeping files) are always present: