Oke AB mag = -2.5 log10(fnu) - 48.60, where fnu is in erg/s/cm^2/Hz
Oke AB mag = 23.9 - 2.5 log10(S/microJy)

To convert an Oke AB mag to an apparent mag, add approximately
-0.8 (U), 0.2 (B), 0.0 (V), -0.2 (R), -0.4 (I)