code: def isOnSilicon(self, ra_deg, dec_deg, padding_pix=DEFAULT_PADDING):
          
          ch, col, row = self.getChannelColRow(ra_deg, dec_deg)
          # Modules 3 and 7 are no longer operational
          if ch in self.brokenChannels:
              return False
          # K2fov encodes the Fine Guidance Sensors (FGS) as
          # "channel" numbers 85-88; they are not science CCDs.
          if ch > 84:
              return False
          return self.colRowIsOnSciencePixel(col, row, padding_pix)
docs: Returns True if the given location is observable with a science CCD.
  
          Parameters
          ----------
          ra_deg : float
              Right Ascension (J2000) in decimal degrees.
  
          dec_deg : float
              Declination (J2000) in decimal degrees.
  
          padding : float
              Objects <=  this many pixels off the edge of a channel are counted
              as inside.  This allows one to compensate for the slight
              inaccuracy in `K2fov` that results from e.g. the lack of optical
              distortion modeling.