National Aeronautics and Space Administration

The Copernicus Archive

Experiment	Raw Data
UCLXE/MSSL	FITS

The Copernicus UCLXE raw data can be selected using the database XCOPRAW available from Browse or directly from the Copernicus FTP area in the HEASARC archive. Data from the UV experiment are available from the STSci archive .

The RAW Copernicus UCLXE data : The original file structure contained an header followed by the data records. Two types of header record were present in the original file storing different parameters. A string set to HEAD or SL identified the header type. The HEAD data are pointed to a source position, instead the SL data are raster scan around the source position. The data records contain the scientific data from all 4 instruments, HK data and pointing constraints. Typically several files contribute to one observation. The data are organized in each FITS file with the same content of the original file. The FITS layout consists of one extension bintable containing both scientific and housekeeping data. The scientific data are stored in the columns CNT_1_3, CNT_3_9, CNT_6_18 and CNT_CPM and are from the 1-3 Å, 3-9 Å, 6-18 Å and the channeltron detectors respectively. There are in total 6563 FITS files. A few data records in the original files had unrecoverable errors. This is less 1 % of the total archive.

The native format of the Copernicus UCLXE data did not contain the pointing position but only the source name and the observation log was not available in a suitable format when the FITS files were created. The coordinates in the fits file were mostly obtained by cross-correlating the object name with various catalogs available from HEASARC and SIMBAD and with the object name listed in the archive of the UV experiment, Princeton Experiment Package, on Copernicus.
For 131 files no matching object name was found in any of the catalogs searched. These files can be identified by the keyword CATID1 and CATALOG set both to 'NONE' and the RA and DEC at 1950 equinox set to -999. The original SL header record did not contain either coordinates or object name. The RA_OBJ, DEC_OBJ, OBJECT keywords, in fits file with IDHEADER=SL, are retained from the HEAD observation immediately preceeding (in time) the current SL file. Offset observations with respect to a source position have coordinates equal to the that source position (e.g. 3U1743-29PT3 is MX1743-29 or PUPPIS A (3) is PUPPIS A).
The observation log was in a form of microfilm and not usable to extract easily coordinates. However we converted the microfilm to gif files (one gif for each microfilm frame). These files are available in the Copernicus FTP area in the HEASARC archive and they can be used to verify the exact pointing.

The FITS files includes data also taken with a 6 channel Pulse Height Analyzer connected with one of the 3 proportional counters, however no response matrix is available to analyse the spectra.