Celestron 82003 Zoom Eyepiece for Regal M2 (Black) This versatile eyepiece is a great addition to your Celestron Regal M2 or upgrade to the standard Trail Seeker zoom eyepiece. Variable Magnification gives you the ability to have a wide field of view for general viewing and detailed up close viewing when needed. Twist-up eyecup and 20 mm eye relief provides a full field of view and comfortable viewing with or without eyeglasses. Fully multi-coated optics increases light transmission through the optical path for brighter images, better contrast and increased resolution. Removing the eyecup exposes threads that can be used to attach a DSLR to the spotting scope for photography.