Using a matrix to position a sprite in XNA

gistfile1.cs

        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            // TODO: Add your drawing code here

            rotation -= 0.03f;
            Vector2 origin = new Vector2(invader.Width / 2, invader.Height / 2);

            //spin in place
            Matrix alienTransform =
                Matrix.CreateRotationZ(rotation) *
                Matrix.CreateTranslation(200, 200, 0);
            
            spriteBatch.Begin(SpriteSortMode.BackToFront, 
                null, null, null, null, null, 
                alienTransform);


            spriteBatch.Draw(invader, //texture2D
                Vector2.Zero, //position
                null,Color.White, 0, 
                origin,// 
                1, SpriteEffects.None, 0);

            spriteBatch.End();

            base.Draw(gameTime);
        }