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A Ginga observation consisted of varying numbers of major frames which had lengths of 4, 32, or 128 seconds, depending on the setting of the bitrate. Each GINGALOG database entry is the first record of a series of observations having the same values of "ACS MONITOR" (Attitude Control System). When this value changes, a new FITS file was written. The other Ginga catalog database, GINGAMODE is also a subset of the same LAC dump file used to create GINGALOG. GINGAMODE contains a listing whenever any of the following changes: "BITRATE", "LACMODE", "DISCRIMINATOR", or "ACS MONITOR". Thus, GINGAMODE monitors changes in several parameters and GINGALOG is a basic log of all the FITS files. Both databases point to the corresponding archived Flexible Image Transport System (FITS) files, but GINGAMODE may have more than one entry for a given FILE_LCURVE in the database. The user is invited to browse though the observations available from Ginga using GINGALOG or GINGAMODE, then extract the FITS files for more detailed analysis.
A Ginga observation consisted of varying numbers of major frames which had lengths of 4, 32, or 128 seconds, depending on the setting of the bitrate. Each GINGAMODE database entry consists of data from the first record of a series of observations having the same values of the following: "BITRATE", "LACMODE", "DISCRIMINATOR", or "ACS MONITOR". When any of these changed, a new entry was written into GINGAMODE. The other Ginga catalog database, GINGALOG is also a subset of the same LAC dump file used to create GINGAMODE. GINGALOG contains a listing only whenever the "ACS monitor" (Attitude Control System) changes. Thus, GINGAMODE monitors changes in four parameters and GINGALOG is a basic log database mapping the individual FITS files. Ginga FITS files may have more than one entries in the GINGAMODE database. Both databases point to the same archived Flexible Image Transport System (FITS) files created from the LAC dump files. The user is invited to browse though the observations available from Ginga using GINGALOG or GINGAMODE, then extract the FITS files for more detailed analysis.
Ginga was the third Japanese X-ray astronomy satellite. It was launched into low Earth orbit on 5th February 1987 and re-entered the atmosphere on 1st November 1991. The scientific payload consisted of the Large Area Counter (LAC; Turner et al. 1989), the All-Sky Monitor (ASM; Tsunemi et al. 1989) and the Gamma-ray Burst Detector (GBD; Murakami et al. 1989). A full description of the satellite is given in Makino et al. (1987). During its lifetime Ginga performed over 1000 pointed observations of approximately 350 different targets, covering all then known classes of cosmic X-ray sources.
The LAC experiment, sensitive to X-rays with energy 1.5-37 keV, was the main scientific instrument aboard Ginga. It was designed and built under a Japan-UK collaboration (ISAS, U. Tokyo, Nagoya U., U. Leicester, Rutherford Appleton Lab). It consisted of an array of eight collimated co-aligned proportional counters with a total effective area of approximately 4000 cm^2. Steel collimators restricted the field of view to 1.1 x 2.0 degrees (FWHM).