USNO Magnitudes versus calibrated

Field RA = 16h18.7m DC = -15°08'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.30 -0.117 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.33
Error cancels for Magnitude 11.2

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.68 -0.050 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = -0.01
Error cancels for Magnitude 13.8

For any comment, contact Jean-Claude PELLE