Filename                               Reason     Bkg         V      RCAM      TCAM   Sigma
20210928.175407.ucomp.637.l1.p3.fts         0    23.9      4.34       0.7       0.3    1.02
20210928.182453.ucomp.637.l1.p3.fts         0    23.3      4.13       0.4       0.3    0.92
20210928.212742.ucomp.637.l1.p3.fts         0    26.5      3.70       0.2       0.2    0.65
20210928.215848.ucomp.637.l1.p3.fts         0    28.7      3.79       0.2       0.1    0.65
20210928.223014.ucomp.637.l1.p3.fts         0    42.8      4.46       0.1       0.0    0.79
20210928.225942.ucomp.637.l1.p3.fts         0    31.3      3.76       0.1       0.0    0.65
20210929.001930.ucomp.637.l1.p3.fts         0    29.1      3.78       0.0       0.1    0.72
20210929.004908.ucomp.637.l1.p3.fts         0    28.2      3.82       0.1       0.1    0.95

GBU bitmask codes
Code    Description
    1   spar guide control loop is below threshold (0.99)
    2   spar guider intensity below threshold (0.9 * 6.551 * exp(-0.05 * secz))
    4   median background is above threshold (45.0)
    8   median background is below threshold (5.0)
   16   spurious Stokes V signal is above threshold (8.0)
   32   the chi-squared of the occulter fit is above threshold (1000.0)
   64   the difference of the image with the median is above threshold (1.8)

* indicates that the threshold values changed on the day