NAME:
  kmphi2
 PURPOSE:   (one line only)
  Basis set function 2 for the HG1G2 photometric system
 DESCRIPTION:
  Based on Muinonen et al, Icarus, 209, 542 (2010).
 CATEGORY:
  Photometry
 CALLING SEQUENCE:
  value=kmphi2(alpha)
 INPUTS:
  alpha - phase angle (degrees)
 OPTIONAL INPUT PARAMETERS:
 KEYWORD INPUT PARAMETERS:
 OUTPUTS:
  return value are the values of the function evaluated for the input
 KEYWORD OUTPUT PARAMETERS:
 CONFIGURATION:
 COMMON BLOCKS:
 SIDE EFFECTS:
 RESTRICTIONS:
 PROCEDURE:
  This uses a lookup table provided in the reference and the built in
    IDL spline procedure.  The derivative constraints are not used.
    An extra grid point is added at high phase to give a more "sensible"
    result.
 MODIFICATION HISTORY:
  Written by Marc W. Buie, Southwest Research Institute, 2024/10/29