qac: Calibration QA Statistics
qac is an ASCII file containing the QA statistics produced by VMBICAL . Prior to the inclusion of GEOMPIPE into VMBICAL , the QA file contained four individual files bundled together as a tar file: qacBAD, qacV, qacM, and qacI. qacBAD contains a label on the first line, followed by a list of "bad" images which have the header keyword FILLED defined and which should be ignored by processing stages subsequent to VMBICAL. The format is the image name followed by "FILLED = no" (or "FILLED = yes"). qacV(M,I) contains a label on the first line, followed by two columns of numbers, the first being the GPS time and the second the average velocity (modulation, intensity). The average is computed over values of radius from 0 to 95% of maximum radius.
With the inclusion of the GEOMPIPE subprocess in VMBICAL, qaz files (qacBAD, geompsf, geomqa, and geomlmb) are bundled into the qac file, for data from 960801 and after qaz files generated for GEOMPIPE include a list of FILLED images, a file containing the Point Spread Function QA parameters generated by GEOM and culled from the image headers, a file containing the HGEOM QA parameters culled from the image headers, and a file containing the updated image geometry ellipse parameters generated by GEOM and culled from the image headers.
These QA parameters include the following:
CHI2 reduced chi-squared of the least-squares fit performed by HGEOM
SLR scattered light ratio
LMB_GRAD gradient at the radius that HGEOM determines to be the "limb"
C_MA corrected major axis
C_MI corrected minor axis
EXT_SLOP slope of the sky extension
A(1) coefficient of the PSF
A(1)_ERR errors of the coefficient
FNDLMBXC X center coordinate
FNDLMBYC Y center coordinate
FNDLMBMI updated minor axis
FNDLMBMA updated major axis
FNDLMBAN ellipse angle
Presently there is also included an additional three individual files: qacB, qacC andqacR for the more recent additions to QA, those being magnetograms, clamp rms and residual velocity.