The premium Astro-Tech 45° viewing angle image erecting diagonal lets you use 1.25 eyepieces for more comfortable terrestrial viewing in catadioptric telescopes with a 1.25 visual back or in refractors with a 1.25 focuser drawtube. It is not usable with reflectors. It increases the magnification approximately 8%.
The diagonal is exceptionally well made. The precision image-erecting Schmidt prism is made of costly BaK-4 glass and is fully multicoated for high light transmission. A non-marring brass compression ring with a thumbscrew holds eyepieces firmly in place.
There is a slanted-side safety groove cut into the 1.25 chrome tube that slips into the telescope focuser. Its slanted sides catch the focuser thumbscrew to keep the image erector from falling out of the eyepiece holder should the thumbscrew accidentally loosen in use. The inside of the 1.25 tube has anti-reflection threading for enhanced image contrast. The 1.25 tube is also threaded for filters. Dust caps are provided for both ends of the image erector.
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