docs: def _solidAngleCMD(self):
          """
          Compute solid angle within the mask annulus (deg^2) as a
          function of color and magnitude.
          """
  
          self.solid_angle_cmd = np.zeros([len(self.roi.centers_mag),
                                              len(self.roi.centers_color)])
  
          for index_mag in np.arange(len(self.roi.centers_mag)):
              for index_color in np.arange(len(self.roi.centers_color)):
                  # mag and color at bin center
                  mag = self.roi.centers_mag[index_mag]
                  color = self.roi.centers_color[index_color]
  
                  if self.config.params['catalog']['band_1_detection']:
                      # Evaluating at the center of the color-mag bin, be consistent!
                      #mag_1 = self.roi.centers_mag[index_mag]
                      #color = self.roi.centers_color[index_color]
                      #mag_2 = mag_1 - color
                      # Evaluating at corner of the color-mag bin, be consistent!
                      mag_1 = mag + (0.5 * self.roi.delta_mag)
                      mag_2 = mag - color + (0.5 * self.roi.delta_color)
                  else:
                      # Evaluating at the center of the color-mag bin, be consistent!
                      #mag_2 = self.roi.centers_mag[index_mag]
                      #color = self.roi.centers_color[index_color]
                      #mag_1 = mag_2 + color
                      # Evaluating at corner of the color-mag bin, be consistent!
                      mag_1 = mag + color + (0.5 * self.roi.delta_color)
                      mag_2 = mag + (0.5 * self.roi.delta_mag)
  
                  # ADW: Is there a problem here?
                  #self.solid_angle_cmd[index_mag, index_color] = self.roi.area_pixel * np.sum((self.mask_1.mask > mag_1) * (self.mask_2.mask > mag_2))
  
                  # ADW: I think we want to keep pixels that are >= mag
                  unmasked_mag_1 = (self.mask_1.mask_annulus_sparse >= mag_1)
                  unmasked_mag_2 = (self.mask_2.mask_annulus_sparse >= mag_2)
                  n_unmasked_pixels = np.sum(unmasked_mag_1*unmasked_mag_2*self.frac_annulus_sparse)
  
                  #n_unmasked_pixels = np.sum((self.mask_1.mask_annulus_sparse > mag_1) \
                  #                               * (self.mask_2.mask_annulus_sparse > mag_2))
  
                  self.solid_angle_cmd[index_mag, index_color] = self.roi.area_pixel * n_unmasked_pixels
          if self.solid_angle_cmd.sum() == 0:
              msg = "Mask annulus contains no solid angle."
              logger.error(msg)
              raise Exception(msg)
  
          return self.solid_angle_cmd