Kasai Trading 1.25" Erecting Zenith Prism (EZP) Diagonal

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Original manufacturer description below.
The Kasai 1.25" Erecting Zenith Prism Diagonal contains an oversized (55mm width) amici-prism, guiding the light path to be reflected twice on either flat roof surface. As a result, the light path comes at 90-degree direction, yielding right-side-up erecting images. And unlike a normal erecting prism, there are no ridgelines on the reflective surfaces, so it can keep good image quality with no deterioration. Therefore, it's very suitable for high magnification planetary observations.
The clear aperture diameter is 27.5mm, causing no vignetting even when using a long focus, wide field eyepiece. The total reflectivity is nearly 100%, so it's also suitable for deep-sky observations. Of course it's very nice for terrestrial viewings, too. The light path length is 109mm - shorter than many 2" diagonal mirrors, so it can reach the focus with vitually all refractors or cassegrains that can be reach focus with a 2" diagonal. All the housing parts are made of durable metal (aluminum alloy) and the prism surfaces are fully multi-coated.
The weight is 660g. (This item is jointly developed with BinoTechno, so "Kasai and BinoTechno" logo is engraved on the side.)
As an additional function, the positions of the nosepiece and the eyepiece adapter can be switched left to right / right to left easily, making a reversed version.
Please note that these are sold individually. But with the use of 2 EZP's (one is normal and the other is reversed) and 2 small refractors, you can complete a set of erect-image binocular telescopes instantly!
Other Information
- Country of Manufacture: Japan
Original manufacturer description below.
The Kasai 1.25" Erecting Zenith Prism Diagonal contains an oversized (55mm width) amici-prism, guiding the light path to be reflected twice on either flat roof surface. As a result, the light path comes at 90-degree direction, yielding right-side-up erecting images. And unlike a normal erecting prism, there are no ridgelines on the reflective surfaces, so it can keep good image quality with no deterioration. Therefore, it's very suitable for high magnification planetary observations.
The clear aperture diameter is 27.5mm, causing no vignetting even when using a long focus, wide field eyepiece. The total reflectivity is nearly 100%, so it's also suitable for deep-sky observations. Of course it's very nice for terrestrial viewings, too. The light path length is 109mm - shorter than many 2" diagonal mirrors, so it can reach the focus with vitually all refractors or cassegrains that can be reach focus with a 2" diagonal. All the housing parts are made of durable metal (aluminum alloy) and the prism surfaces are fully multi-coated.
The weight is 660g. (This item is jointly developed with BinoTechno, so "Kasai and BinoTechno" logo is engraved on the side.)
As an additional function, the positions of the nosepiece and the eyepiece adapter can be switched left to right / right to left easily, making a reversed version.
Please note that these are sold individually. But with the use of 2 EZP's (one is normal and the other is reversed) and 2 small refractors, you can complete a set of erect-image binocular telescopes instantly!
Original manufacturer description below.
The Kasai 1.25" Erecting Zenith Prism Diagonal contains an oversized (55mm width) amici-prism, guiding the light path to be reflected twice on either flat roof surface. As a result, the light path comes at 90-degree direction, yielding right-side-up erecting images. And unlike a normal erecting prism, there are no ridgelines on the reflective surfaces, so it can keep good image quality with no deterioration. Therefore, it's very suitable for high magnification planetary observations.
The clear aperture diameter is 27.5mm, causing no vignetting even when using a long focus, wide field eyepiece. The total reflectivity is nearly 100%, so it's also suitable for deep-sky observations. Of course it's very nice for terrestrial viewings, too. The light path length is 109mm - shorter than many 2" diagonal mirrors, so it can reach the focus with vitually all refractors or cassegrains that can be reach focus with a 2" diagonal. All the housing parts are made of durable metal (aluminum alloy) and the prism surfaces are fully multi-coated.
The weight is 660g. (This item is jointly developed with BinoTechno, so "Kasai and BinoTechno" logo is engraved on the side.)
As an additional function, the positions of the nosepiece and the eyepiece adapter can be switched left to right / right to left easily, making a reversed version.
Please note that these are sold individually. But with the use of 2 EZP's (one is normal and the other is reversed) and 2 small refractors, you can complete a set of erect-image binocular telescopes instantly!
Other Information
- Country of Manufacture: Japan
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Kasai Trading 1.25" Erecting Zenith Prism (EZP) Diagonal


















