Kasai BinoTechno EZP-R Erecting Zenith Prism

Kasai BinoTechno EZP-R Erecting Zenith Prism

A right-angle viewing device for refractors/cassegrains, yielding right-side-up erecting images and very suitable for high power observations with no ridgeline throughout the light path.

The Kasai 1.25" Erecting Zenith Prism Diagonal contains an oversized (55 mm 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. Kasai Trading has a video about the light path, showing why there is no ridgeline (and why the prism is oversized - related!), it can be found here.

The clear aperture diameter is 27.5 mm, 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 109 mm - 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 660 g. (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.

With the use of 2 EZPs (one is normal and the other is reversed) and 2 small refractors, you can complete a set of erect-image binocular telescopes instantly!

Low-Power (Deep-Sky & Terrestrial) Observations
EZP is an ideal 90-degree viewing device for low-power observations of faint deep-sky objects, as it does not vignette the field of view even with ultra-wide and long focus eyepieces, and provides nearly 100% reflectivity. Of course it can be used comfortably for terrestrial viewings, too, as it provides perfectly right-side-up erecting images.

High Power (Lunar, Planetary and Double Stars) Observations
High magnification observations are where the true potential of EZP can be best demonstrated. With no deterioration in sharpness due to the two reflections on the high-precision flat surfaces, it can maintain very crisp images of the moon, planets, and double stars up to the highest magnifications. In addition, since perfectly right-side-up erecting images can be obtained, it is widely recommended to many telescope users who feel uncomfortable with the mirror-reversed images with a diagonal mirror or prism, or who are dissatisfied with the image deterioration with conventional erecting prisms.

Safety informations: PDF Download