The Celestron Omni XLT 150mm (6") f 5 Refractor is for intermediate users & combines high-quality optics with an elegant, portable design that's ideal for general observation of deep sky objects. The Star Bright XLT optical coatings maximise light transmission & reduce internal reflections for the brightest possible images. The CG-4 German equatorial mount helps you navigate the night sky quickly & track objects smoothly. Using aspheric shaping technology in conjunction with h&-figuring the optics, the Omni XLT presents an image with virtually no spherical aberration.