To date it has not been possible to determine valid extinction coefficients for
either the J, H, or K bands in the infrared.  Instead, the literature values
determined by Frogel (http://adsabs.harvard.edu/abs/1998PASP..110..200F), 
namely 0.100, 0.055 and 0.085, are used for calculating the zeropoints in
J, H, and K, respectively.