This is a very nice modular measuring microscope system manufactured by Miruc Optical of Japan. It was sold in the USA by E.P.O.I (Ehrenreich Photo Optical Industries), a company that was the sales agency for early Nikon microscopes.

Miruc Optical is still a vital company and several parts of this instrument are still in their product line. This microscope is highly modular, so I will first describe the four individual modules that comprise this instrument.

The uppermost item is the large field 10x measuring ocular. It has an adjustable diopter ring (hence the ‘D’ marking) and has a reticle holder for interchangeable reticles. This ocular has a simple crossline reticle installed (reticles are 24 mm in diameter). Miruc part number for the crossline reticle is 31-C. No eyeguard is included with the ocular. Current version of the ocular is part number OC WFD 10X. It differs mostly in that the barrel is now all anodized aluminum. Ocular sleeve diameter is 30 mm.

The next component of the microscope is the goniometer head. This module fits into the 28 mm bore of the microscope tube, and the upper part accepts the standard 30 mm diameter oculars. The length of the assembly is 49 mm (not including lower mounting sleeve). The ocular carrier can be rotated 360 degrees, and its position read directly to 10 minutes of arc – individual degree graduations on the rotating ring, and a vernier on the collar reading to 10 minutes). The goniometer may be set to zero and the crossline ocular rotated independently of the goniometer scale for greater ease in making measurements. Ocular position is locked in place via a clamping screw. Overall scale diameter is 78 mm, the rotating portion is 69 mm. It is very finely divided. The goniometer accessory is no longer supplied by Miruc.

The next component is the microscope body proper. This item most closely resembles the current MF-45 system which has a 45 degree angle and image erecting roof prism. The other feature of this module is the shortened barrel length so it can accommodate different measurement accessories such as the above goniometer attachment. Miruc also makes a filar type attachment which could be used instead of the goniometer. When neither attachment was ordered, an extension sleeve of 49 mm length was supplied. (No extension sleeve is supplied with this listing). The mounting sleeve of the microscope is 32 mm in diameter and approximately 30 mm long, not including the length of the clamping capstan ring. The base of the mounting sleeve has a slightly recessed RMS objective thread.

The last component in the system is a very nice pancratic objective lens with a fixed working distance of approximately 75 mm (this was a rough measurement on my part, not a part of the actual specification). The zoom range is continuous from 0.8x to 4x (5:1 zoom ratio). Only the large milled ring turns while zooming – the lower portion of the objective (dark gray part) remains fixed thereby making the mounting of illuminators much more practical. This version of the objective is no longer produced – the newer version has a slightly larger zoom range of 0.7x to 4.5x and is a bit more compact.

The microscope is in excellent condition as can be seen from the photos. The glass is all nearly flawless, and there are only a couple of minor chips in the paint, mostly on the lower collar of the zoom objective (probably from where an illuminator was clamped).We did not get either the focus block or stand with this microscope. However, Miruc still manufactures a complete line of focusing blocks and stands suitable for this instrument, or you can devise your own mounting system. This is a very versatile instrument.



Location MB 29.4

Photo set 257..