USNO Magnitudes versus calibrated

Field RA = 09h18.9m DC = +29°04'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.94 -0.126 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = +0.17
Error cancels for Magnitude 15.4

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.12 -0.069 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.15
Error cancels for Magnitude 16.2

For any comment, contact Jean-Claude PELLE