Here we have a really capable M25 binocular microscope by well-known British optical manufacturers Cooke Troughton & Simms (CTS) of York. This is a well-specified example, probably dating from around the late 1950s or early 1960s when this instrument would have been a cutting-edge design and was probably used in a research lab or similar setting. The M25 model was first introduced by CTS in 1954, with the final examples produced during the mid-1960s when the CTS brand name was dropped by owners Vickers Instruments.
The condition is generally really good and the instrument has recently been cleaned, checked over and given a light lubrication, with everything working as it should. Turning to the main technical details of this quality vintage M25 binocular microscope set-up, we have a rotatable (full 360 degrees) binocular eyepiece unit that's adjustable for both focus by gently twisting the eyepiece tubes and eyepiece separation by gently pulling on the adjustment tabs. These binocular units are fixed at +1.5x magnification and effectively provide a 50% magnification boost to the eyepieces. It's also supplied with a pair of period 8x magnification compensating eyepieces, which therefore scale up to 12x magnification taking account of the increase afforded by the binocular unit. There's also two more pairs of non-CTS eyepieces in the case.The coarse focus system moves the main microscope frame in a vertical plane, with its controls at the base of the frame. There is a nice smooth action through the twin-sided thumb-wheels - travel and focus are both good.
Note that the frame on this model of microscope is not designed to tilt. Fine focus adjustment essentially works within the main focus adjustment when smaller inputs are made via the concentric fine focus thumb-wheels - interestingly in the M25 model the fine focus moves the stage - whereas the coarse focus moves the main microscope upper frame - another innovative and patented CTS feature.There are five quality objective lenses in total by Cooke and Lomo with a usable selection of progressive magnification and a rotating 4-way turret which clicks into place positively as each objective is rotated into its viewing position. The objective lenses are as follows and all have storage canisters. Lomo - 20x CTS - 40x. CTS - 95x - oil immersion - not tested with oil. (The effective overall magnification therefore ranges from about 40x to 1,140x when using oil immersion with good illumination). The specimen stage is fully mechanical being a CTS design with twin concentric thumb-wheel x-axis and y-axis controls located on both sides of the stage, plus there's a slide holder mechanism for holding samples in place during viewing sessions, which has a movable armature on the RHS. The stage mechanisms run nice and smoothly and there's only minor signs of wear to the stage surface. Below-stage there is a CTS condenser in a height adjustable dovetail-fit mount with centering and an iris for controlling light levels, plus there's a 32mm swing out filter carrier for adding coloured, opaque or dark-field filters. Sample illumination is provided via a sub-stage mirror assembly with plano-concave mirror in a rotating gimbal mount that's got very good silvering and just a few minor signs of foxing in keeping with the instrument's age. The overall condition of this technically capable M25 microscope is really extremely good with no maintenance issues and it only has very minor signs of wear to the paint finish on the frame in areas where one would expect to see some signs of use for a vintage piece of technical equipment. There is also a correct CTS hardwood storage case with this microscope with internal racking, carry-handle and working lock and key. In summary, this is a fairly rare and well-equipped vintage technical binocular microscope from British optical firm CTS together with a substantial storage case, which makes a rather attractive microscopy set-up. It may therefore appeal to both specialist collectors of technical equipment and of course those seeking a CTS M25 model for its technical capabilities and imposing retro look, which could also make it a spectacular display piece. It's supplied with a good range of CTS/Lomo objective lenses and fitted with a mechanical stage which is a must for high-magnification use. It's essentially usable out of the box with a bit of time spent getting to know it and setting up its many features and controls for optimum viewing results depending on application. This microscope equipment will be partially dismantled and very well packaged for transport. It will be dispatched by insured courier upon receipt of cleared funds.
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