USNO Magnitudes versus calibrated

Field RA = 07h03.8m DC = -03°51'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.51 -0.121 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.18
Error cancels for Magnitude 12.5

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.79 -0.041 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.23
Error cancels for Magnitude 19.6

For any comment, contact Jean-Claude PELLE