USNO Magnitudes versus calibrated

Field RA = 21h42.8m DC = +43°36'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.00 -0.091 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.27
Error cancels for Magnitude 11.0

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.55 -0.091 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.27
Error cancels for Magnitude 17.0

For any comment, contact Jean-Claude PELLE