GINGALOG - Ginga LAC Log Catalog
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 mission is described by Makino et al. (1987, Astrophys. Letters Commun., 25, 223) and the instrument by Turner et al. (1989, Publ. Astron. Soc. Japan, 41, 345). Some of the present documentation has been adapted from these papers.
Time of the start of the first record of an observation. An observation consists of those records in the GINGAMODE file that consecutively have the same ACS (Attitude Control System) value.
Time of the stop of the last record of an observation.
The total length of time in this observation interval.
The on-time in this observation. A sum of the live times in this interval.
Designates the spacecraft mode during a particular ACS (Attitude Control System) Mode. Settings include: NML (Normal), SL+ (Slewing positive), SL- (Slewing negative), MAN (Maneuver), S36 (Slew through 360 degrees), STB (STand By), LSP (Low SPin) and NAT (No ATtitude solution).
The right ascension for this LAC observation.
The declination for this LAC observation.
The galactic longitude for this LAC observation.
The galactic latitude for this LAC observation.
The name of the spacecraft target. If the target was unknown or contained multiple source, this value may be 'N/A' (not applicable). Some observations contain more than one source because the ACS Monitor value remained constant while the spacecraft changed targets.
The name for the FITS file corresponding to one entry in this database. The FITS files have the form: GYYMMDD_HHMMSS_xz.FITS; G (for Ginga Large Area Counter experiment); the year, month, day, hours, minutes, and seconds of the start of the observation; x, which can be P for pointing, meaning the entire file was 'on-target', S for slewing, or O for other, meaning that standby or no attitude solution occurred in this file); z, which can be 'C' for continuous BITRATE (the value for bitrate within this file is the same for all rows, that is: the timebin size is constant, either 4, 32 or 128 seconds) or 'M' for mixed BITRATE (this file contains one or more bitrates, that is: this file contains rows that vary in length, but the file also contains a TIMEDEL keyword and a FRACEXP (fractional exposure) keyword to normalize the count rates. A typical Ginga FITS file name would be G870305_120455_PC.FITS.