This versatile 50mm aperture guide scope with a built-in helical focuser for precise focusing of potential guide stars.Designed for use with the guider CCD astronomy camera or eyepiece. It is an ideal accessories to any astrophotographers. Extinction design of telescope. Taper matt tooth and spray matting paint design can greatly reduce the light loss of light in the entire lens barrel, making the image clearer and sharper; Unique design with double protection to avoid loss of light, making the images you observe clearer and sharper. Lightweight and portable. 604g and 240mm total length that is very small and compact autoguiding system adds hardly any weight to an astrophotography setup. SV135 eyepiece is a good assistant for you to observe and take pictures of the planets. More comfortable to view the moon, Jupiter and Saturn. 36°-52° field of view. This is a zoom eyepiece considering that it zooms from 7mm to 21mm. which allows you to see different wide field of view under the same viewing conditions. Meet your different needs. Provide comfortable observation experience. 13-14mm wide eye relief can also provide an easy and pleasant viewing experience. It is also friendly to people wearing glasses.