USNO Magnitudes versus calibrated

Field RA = 07h38.0m DC = -25°57'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = -0.23 -0.011 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.39
Error cancels for Magnitude -20.6

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.32 -0.032 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = -0.13
Error cancels for Magnitude 10.1

For any comment, contact Jean-Claude PELLE