USNO Magnitudes versus calibrated

Field RA = 01h36.3m DC = +15°45'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.29 -0.114 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.31
Error cancels for Magnitude 11.3

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.63 -0.104 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.16
Error cancels for Magnitude 15.6

For any comment, contact Jean-Claude PELLE