|
Description
The GINGALOG database table contains selected information from the Large Area Counter (LAC) aboard the third Japanese X-ray astronomy satellite Ginga. The Ginga experiment began on day 36, 5 February 1987 and ended in November 1991. Ginga consisted of the LAC, the all-sky monitor (ASM) and the gamma-ray burst detector (GBD). The satellite was in a circular orbit at 31 degree inclination with apogee 670 km and perigee 510 km, and with a period of 96 minutes. 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. The Ginga LAC Log Catalog was prepared from data sent to NASA/GSFC from the Institute of Space and Astronautical Science (ISAS) in Japan. This is a service provided by NASA HEASARC .
|
