USNO Magnitudes versus calibrated

Field RA = 01h51.1m DC = -03°33'

Fig 1. USNO 'B' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.98 -0.152 * B_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'B' = -0.15
Error cancels for Magnitude 13.0

Fig 2. USNO 'R' Magnitude Error f(Magnitude)
Red = USNO - Calibrated
Yellow = Best Fit: Y = +1.35 -0.087 * R_cal
Y vertical Tick = 0.1 magnitude
Offset for Magnitude 14.0 'R' = +0.14
Error cancels for Magnitude 15.6

For any comment, contact Jean-Claude PELLE