code: def ToOBMag(self, wave, flux, area=None):
          
          area = area if area else refs.PRIMARY_AREA
          bin_widths = \
              binning.calculate_bin_widths(binning.calculate_bin_edges(wave))
          arg = flux * bin_widths * area
          return -1.085736 * N.log(arg)
docs: Convert to ``obmag``.
  
          .. math::
  
              \\textnormal{obmag} = -2.5 \\; \\log(\\delta \\lambda \\; \\times \\; \\textnormal{area} \\; \\times  \\; \\textnormal{photlam})
  
          where :math:`\\delta \\lambda` represent bin widths derived from
          :func:`~pysynphot.binning.calculate_bin_edges` and
          :func:`~pysynphot.binning.calculate_bin_widths`, using the input
          wavelength values as bin centers.
  
          Parameters
          ----------
          wave, flux : number or array_like
              Wavelength and flux values to be used for conversion.
  
          area : number or `None`
              Telescope collecting area. If not given, default value from
              :ref:`pysynphot-refdata` is used.
  
          Returns
          -------
          result : number or array_like
              Converted values.