USNO Magnitudes versus calibrated

Field RA = 00h19.7m DC = +21°49'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.41 -0.111 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.15
Error cancels for Magnitude 12.7

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +2.00 -0.129 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.20
Error cancels for Magnitude 15.5

For any comment, contact Jean-Claude PELLE