Xinda LE - T Series Adjustable Eyepiece —— LE - T SERIES ADJUSTABLE EYEPIECE. —— 1.25 inches / Metal structure / Multi - layer optical coating / Rotating eyecup Brand: SKY - WATCHER Exit Pupil Distance: 20MM Model: LE9T / LE15T Lens Diameter: 19MM Eyecup: Rotating Eyecup Interface Size: 1.25 inches Coating: FMC Full - surface Multi - layer Coating Eyepiece Field of View: 50° Focal Length: 9MM / 15MM Optical Structure: 6 Elements in 3 Groups When used on an astronomical telescope, the smaller the focal length of the eyepiece, the greater the magnification. The larger the focal length of the eyepiece, the lower the magnification. During observation, a high - power telescope can observe details and other objects, while a low - power eyepiece can observe landscapes, nebulae and other objects with a relatively wide area, making it convenient to find their detailed targets.