USNO Magnitudes versus calibrated

Field RA = 12h25.4m DC = +20°06'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +2.09 -0.161 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.17
Error cancels for Magnitude 12.9

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.89 -0.076 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = -0.17
Error cancels for Magnitude 11.7

For any comment, contact Jean-Claude PELLE