USNO Magnitudes versus calibrated

Field RA = 04h59.7m DC = +19°28'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.04 -0.022 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.27
Error cancels for Magnitude 1.8

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.49 -0.019 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.23
Error cancels for Magnitude 26.2

For any comment, contact Jean-Claude PELLE