Olympus CT5 Centering Telescope - 23mm

The Olympus CT5 centering telescope is an indispensable alignment tool for phase contrast microscopy on instruments equipped with 23mm eyetubes. In a phase contrast system, the condenser annulus must be precisely centered within the objective’s phase ring to produce the characteristic high-contrast, halo-free image of transparent specimens. Misalignment results in reduced contrast, asymmetric halos, and imaging artifacts that can obscure fine specimen detail or lead to misinterpretation. The CT5 is inserted into one eyepiece tube in place of the standard eyepiece, allowing the user to directly observe the back focal plane of the objective and visually align the condenser annulus to the phase ring using the condenser centering screws. This procedure is quick, straightforward, and must be repeated whenever the objective or condenser is changed. The 23mm barrel diameter fits all microscopes with standard 23mm eyetubes — including Olympus CH, BH, CK, and other classic Olympus platforms, as well as many other manufacturers’ microscopes using the 23mm standard. Supplied as a genuine Olympus OEM component (part no. 2-P791) in new condition.