The SV231 color correction filter is designed with full thread and standard size to compatible with different types of telescope. High transmittance means high level of transparency, allows a significant amount of light or energy to transmit through it. You can use the SV231filter with SV48P telescope for astronomical observations without color difference to obtain the most exquisite details of lunar craters and planetary surfaces. When the telescope is pointed at or near the zenith (directly overhead), mirror diagonal telescope allows for more convenient and comfortable observation. SV188P uses a high-reflective dielectric coating that can achieve a reflectivity of 99%; more light means you will get brighter pictures. Just like looking in a mirror, the image is correct up and down; left and right are flipped.