USNO Magnitudes versus calibrated

Field RA = 08h51.4m DC = +11°48'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.61 -0.116 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.01
Error cancels for Magnitude 13.9

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.44 -0.089 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.19
Error cancels for Magnitude 16.2

For any comment, contact Jean-Claude PELLE