High quality optical Prism inside rather than a mirror which makes your image clear and sharp
More comfortable viewing orientation as you observe from above, filter thread for any 1.25 inch filter; accepts standard 1.25 inch eyepieces
Protective coating on the mirror to ensure a long life; metal barrel for secure seating in the focuser
1.25 inch O-III Filter greatly enhances contrast during visual observation of gaseous and planetary nebulae in all sky conditions; astrophotographic 1.25 inch filter allows high-contrast imaging even in areas with strong light pollution
Especially useful for large aperture telescopes through which the light of the Moon can be extremely overwhelming; allow just for the double Ionized Oxygen lines between 496nm to 501nm to pass through at 95 percent