USNO Magnitudes versus calibrated

Field RA = 20h07.8m DC = +17°41'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
 Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.36 -0.059 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.47
Error cancels for Magnitude 6.1

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
 Red = USNO - Calibrated
Yellow = Best Fit: Y = -0.15 -0.001 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = -0.17
Error cancels for Magnitude -152.1