Camera Orbit C# Unity

using UnityEngine;
using System.Collections;

public class CameraOrbit : MonoBehaviour {

public GameObject target = null;
public bool orbitY = false;

// Use this for initialization
void Start () {

System.GC.Collect();

}

// Update is called once per frame
void Update () {

if (target != null)
{
transform.LookAt(target.transform);
if (orbitY)
{
transform.RotateAround(target.transform.position, Vector3.up, Time.deltaTime * 5);

}

}
}
}