The Alstar 12.5mm Illuminated Reticle Plossl Telescope Eyepiece is ideally suited for guiding astrophotos when used in off-axis guiders or guide scopes. The extremely fine, illuminated double crosshairs make tracking the guide star much straightforward for you. Instead of having to cover the star, as with single crosshairs, you can keep it precisely positioned in the centre of the eyepiece. Any deviation from this position is noticed immediately, and in time to be able to react.The eyepiece has a red LED light source for illuminating the crosshairs. This is steplessly adjustable via a knob on the side of the eyepiece. There is also a separate dioptre adjuster for you to be able to bring both the star and the crosshairs into focus simultaneously.The 12.5mm eyepiece provides magnification that is sufficiently high for allowing good precision guiding. This Ploessl design 1.25” eyepiece has four multi-coated lenses, providing a 40° low-reflection field of view.There are also other uses for your crosshair eyepiece. These eyepieces are also very useful for determining the field of view, aligning a mount, or for finding the position angles of double stars.Perfectly guided astrophotos are no secret, but rather the result of using the right accessories.