Вопрос про _rotation

[crazyone]

function test(target1, target2) {
	var xm = target2._x;
	var ym = target2._y;
	target1.destrot = (Math.atan((ym-target1._y)/(xm-target1._x))*180)/Math.PI;
	if (xm<target1._x) {
		target1.destrot = target1.destrot+180;
	}
	target1.onEnterFrame = function () {
		trace(this.destrot);
		this._rotation += (this.destrot-this._rotation)/4;
	};
}