Filename                               Reason     Bkg         V      RCAM      TCAM   Sigma
20210826.181009.ucomp.637.l1.p7.fts        52   135.6    855.30    1935.0    2759.5     NaN
20210826.183430.ucomp.637.l1.p7.fts        20    72.2     95.35       0.0       0.0     NaN
20210826.200826.ucomp.637.l1.p7.fts        16    34.3     17.33       0.0       0.0     NaN
20210826.203439.ucomp.637.l1.p7.fts        16    36.1     17.34       0.0       0.0     NaN
20210826.205910.ucomp.637.l1.p7.fts        16    37.9     17.61       0.0       0.0     NaN
20210826.212533.ucomp.637.l1.p7.fts        16    39.0     17.63       0.0       0.0     NaN

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