You can use SV48P telescope the with SV231filter for astronomical observations without color difference to obtain the most exquisite details of lunar craters and planetary surfaces. The SV48P telescope features fully multi-coated lenses to maximize light transmission and eliminate chromatic aberration, bringing you the true colors of the nebula. 90mm objective lens collects a large amount of light thereby providing an enhanced and brighter field of view. 360 degrees is convenient for your photographic composition and visual observation. The gear ratio of the dual-speed 2-inch toothed focuser is 1:10. The combination of constant speed and micro-speed makes it easy to achieve precise focusing and helps you obtain a clear and bright observation target. Correct chromatic aberration; SV231 telescope filter prevents unwanted color banding in the blue spectral range; minimizes blue wavelengths in out-of-focus areas OD＞4; the higher the filter cut-off depth; the smaller the noise and the higher the imaging contrast. 1.25 in diagonal fits telescopes with 1.25in focusers. Accepts standard 1.25” eyepieces, filters, Barlow lenses and other accessories with a 1.25in insert barrel. 90° Viewing Angle. For more comfortable overhead viewing through refractor and Cassegrain type telescopes.