USNO Magnitudes versus calibrated

Field RA = 07h04.1m DC = -03°52'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.27 -0.105 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.20
Error cancels for Magnitude 12.1

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.53 -0.023 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.21
Error cancels for Magnitude 23.2

For any comment, contact Jean-Claude PELLE