USNO Magnitudes versus calibrated

Field RA = 17h41.2m DC = +27°36'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = -0.32 -0.024 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.66
Error cancels for Magnitude -13.1

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +0.45 -0.034 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = -0.04
Error cancels for Magnitude 13.0

For any comment, contact Jean-Claude PELLE