USNO Magnitudes versus calibrated

Field RA = 08h35.3m DC = +28°28'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.60 -0.130 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.22
Error cancels for Magnitude 12.3

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.29 -0.098 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = -0.08
Error cancels for Magnitude 13.2

For any comment, contact Jean-Claude PELLE