code: def plotSpacecraftYAxis(self, maptype=None):
          
  
          if maptype is None:
              maptype=self.defaultMap
          #Plot direction of spacecraft +y axis. The subtraction of
          #90 degrees accounts for the different defintions of where
          #zero roll is.
          yAngle_deg = getSpacecraftRollAngleFromFovAngle(self.roll0_deg)
          yAngle_deg -=90
  
          a,d = gcircle.sphericalAngDestination(self.ra0_deg, self.dec0_deg, -yAngle_deg, 12.0)
          x0, y0 = maptype.skyToPix(self.ra0_deg, self.dec0_deg)
          x1, y1 = maptype.skyToPix(a, d)
          mp.plot([x0, x1], [y0, y1], 'k-')
docs: Plot a line pointing in the direction of the spacecraft
          y-axis (i.e normal to the solar panel