USNO Magnitudes versus calibrated

Field RA = 17h03.1m DC = +21°39'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.72 -0.073 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.30
Error cancels for Magnitude 9.9

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.00 -0.067 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.05
Error cancels for Magnitude 14.8

For any comment, contact Jean-Claude PELLE