anchor.diff:          int x,y;
           double diff;
           for (ObservatorySession session in sessions.values) {
  -            print("doing a thing to $session with ${session.x} and ${gridsize} and ${session.model_offset_x} and ${camx}");
  +           // print("doing a thing to $session with ${session.x} and ${gridsize} and ${session.model_offset_x} and ${camx}");
               x = ((session.x + 0.5) * gridsize).floor() + session.model_offset_x - this.camx;
               y = ((session.y + 0.5) * gridsize).floor() + session.model_offset_y - this.camy;
   
  
positive.code:             ..render(this.renderScene, this.renderCamera);
      }
  
      void updateSessions() {
          double leftedge   = this.camx - this.canvasWidth  / 2;
          double rightedge  = this.camx + this.canvasWidth  / 2;
          double topedge    = this.camy - this.canvasHeight / 2;
  
negative.code:         }
      }
  
      Future<Null> goToCoordinates(num x, num y) async {
          x = x.floor();
          y = y.floor();
  
  