The SV550 APO refractor is a compact refractor with 122mm aperture, f/7 focal ratio and 854mm focal length, a great travel telescope for astrophotography and observation. The OTA weighs 6.44kg/ 14.18lb, easy to carry out when fitting into the carrying case. The APO refractor features a 122mm aperture which gathers more light, and offers more clear and detailed images, suitable for deep sky photography and observation,and even some fainter deep sky objects, due to the higher limiting magnitude. The SV550 122mm adopts a FPL-51 triplet apochromatic lens structure which contains one piece of ED glass. The triplet lens provides better correction of aberration and greatly reduces chromatic aberration and enhance the clarity and sharpness. The gear ratio of the dual speed 2.5-inch toothed focuser is 1: 10, which makes it easy to achieve accurate focus. The dual speed focuser can provide two focusing speeds by using a set of co-axial knobs, for fast focusing and fine focusing. The 122mm fully multi-coated objective lens and the knife-edge baffle ensure high transmittance while reduces stray light, for a brighter aperture, and clear, sharp and high-contrast images. The length of the dovetail is as high as 300mm, which is longer than the length of most dovetails on the market. It can maintain the balance to the greatest extent, and it will be more convenient in the adjustment process. The entire tube rings have 26 screw holes, compatible with more equipment installations, like Smart WIFI device, guide scope, astronomy camera etc., meeting various needs of installations. SV165 Mini Guide Scope Support sensitive auto guiding cameras for easy guide star acquisition. Compact and highly sensitive 1.23-megapixel color camera with 1/3” CMOS 1280x960 sensor perfect for autoguiding or planetary imaging; small 3.75-micron pixels; high peak QE of 80% and low read noise allows tight tracking of faint guide stars.