USNO Magnitudes versus calibrated

Field RA = 05h26.4m DC = +24°51'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = -0.17 -0.026 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.54
Error cancels for Magnitude -6.5

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.05 -0.053 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.31
Error cancels for Magnitude 19.8

For any comment, contact Jean-Claude PELLE