USNO Magnitudes versus calibrated

Field RA = 20h35.4m DC = -18°31'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.98 -0.129 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = +0.17
Error cancels for Magnitude 15.3

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = -0.25 +0.020 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.02
Error cancels for Magnitude 12.8

For any comment, contact Jean-Claude PELLE