APM 2″ zenith prism
If you are looking for a reliable and precisely crafted zenith prism for your telescope, the APM 2″ zenith prism is a choice that will not disappoint. It combines quality optical glass, practical design features and universal compatibility - all in a robust body weighing 624 g, which radiates solidity with every touch.
Optical performance
At the heart of the prism is an optical block made of K9/BK7 glass with a clear aperture of 43 mm. This aperture ensures that even eyepieces with a wide field of view experience no vignetting, and the full light throughput of the telescope is fully utilised. The optical path length of the prism is 125 mm, which must be taken into account when focusing, particularly with telescopes that have a limited focuser travel range. K9/BK7 glass is a proven optical material with excellent transmission across the visible spectrum and minimal chromatic aberration - a classic you can rely on.
Mechanical construction and usability
APM has not cut corners on the mechanical side either. The quick-release mechanism allows the prism to be attached to the telescope easily and quickly without the use of any tools - you will especially appreciate this when switching between different telescopes or working in the field at night. A ring clamp ensures a firm and secure hold on the eyepiece without any risk of scratching or slipping. In addition, the prism is equipped with a 2″ filter thread, so popular astronomical filters - whether for lunar observation, planetary viewing or emission nebula work - can be screwed directly onto the prism without the need for additional adapters.
Compatibility and included accessories
Included in the package is a 1.25″ to 2″ reduction adapter, so the prism can be used immediately with standard 1.25″ eyepieces as well. The connection to the telescope and to the eyepiece is 2″ in both cases, making it a truly universal accessory for any observatory or mobile observation setup.
About APM Telescopes
APM Telescopes is a German manufacturer and distributor of astronomical optics with a long-standing reputation among demanding amateur astronomers and professionals alike. Their products are characterised by an emphasis on build quality, careful optical control and thoughtfully designed details. The APM 2″ zenith prism is no exception - it is a tool designed for those who do not want to compromise when observing the night sky and demand maximum optical performance and mechanical reliability from their accessories. Whether you are observing planets, double stars or deep-sky objects, this prism will always be ready to enhance your viewing experience.
Technical specifications
| Parameter |
Value |
| Clear aperture |
43 mm |
| Optical glass |
K9/BK7 |
| Optical path length |
125 mm |
| Connection diameter (telescope / eyepiece) |
2″ |
| Filter thread |
2″ |
| Included adapter |
1.25″ to 2″ |
| Eyepiece clamp |
Ring clamp |
| Attachment to telescope |
Quick-release mechanism |
| Weight |
624 g |
| Manufacturer |
APM Telescopes (Germany) |
