USNO Magnitudes versus calibrated

Field RA = 23h42.4m DC = +43°02'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +2.08 -0.142 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = +0.09
Error cancels for Magnitude 14.6

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.19 -0.064 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.30
Error cancels for Magnitude 18.7

For any comment, contact Jean-Claude PELLE