Rotation Script Changes the Object Axis Inclination Too

Hi Everyone,

I have a rotation script for the rotation of a planet (The Earth) but the planet has a 23,67 inclination degrees on its own axis (on the Y rotation vector of the Sphere Object), and the rotation script works fine at any speed until i give the planet object its proper inclination degrees, then , when i change the speed of the rotation, the sphere wont mantain its correct axis and change its inclination, this is the script:

var rotationSpeed: float = 15;

function Update() {		

// planet to spin on it's own axis 
transform.Rotate(transform.up * rotationSpeed * Time.deltaTime, Space.World);

}

Thanks to any Help :)!

I found that using the RotateBehaviour.cs script from the Standard Assets, the sphere object rotates fine on its own pivot center even after of being tilted some degrees, but i need to use it in the javascript code, any idea? thank you:

using UnityEngine;
using System.Collections;

//Decompile by Si Borokokok

public class RotateBehaviour : MonoBehaviour
{
    public Vector3 RotationAmount;

    private void Update()
    {
        transform.Rotate((Vector3) (RotationAmount * Time.deltaTime));
    }
}

SOLVED!, in the first code i changed transform.up for Vector3.up, and its working great now, thanks and hope this helps to anybody with a similar issue, the working code its this:

var rotationSpeed: float = 15;

function Update() {

transform.Rotate(Vector3.up * rotationSpeed * Time.deltaTime, Space.World);

}