USNO Magnitudes versus calibrated

Field RA = 10h18.3m DC = +41°27'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +2.23 -0.146 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = +0.19
Error cancels for Magnitude 15.3

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +2.10 -0.134 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.23
Error cancels for Magnitude 15.7

For any comment, contact Jean-Claude PELLE