USNO Magnitudes versus calibrated

Field RA = 08h13.7m DC = -01°14'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.95 -0.147 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.10
Error cancels for Magnitude 13.3

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.06 -0.073 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.04
Error cancels for Magnitude 14.6

For any comment, contact Jean-Claude PELLE