Filename                               Reason     Bkg         V      RCAM      TCAM   Sigma
20210725.225844.ucomp.656.l1.p7.fts        16    28.2    344.95       3.0       2.8     NaN
20210725.231902.ucomp.656.l1.p7.fts        16    29.3    347.18       3.0       3.2     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 (800.0)
   64   the difference of the image with the median is above threshold (3.0)

* indicates that the threshold values changed on the day