Here we have a really capable and very comprehensive M25 binocular microscope outfit 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 and its associated equipment, we have in summary:
- M25 binocular instrument
- Eleven objective lenses in total - 7 standard and 4 Phase Contrast
- Phase Contrast hardware in separate wooden case
- Illumination via mirror
- Illumination via low voltage illuminator - 6V 15W
- 3 pairs of eyepieces
- Research grade storage case in hardwood
In terms of technical details there's 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 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 giving 6x and 10x magnification options, plus the extra 50% uplift, meaning 9x and 15x are also available at the eyepieces.
The coarse focus system moves the main microscope limb 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 limb 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 limb - another innovative and patented CTS feature.
There are seven 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 nose-piece is also spring-loaded in order to protect the objectives in case they happen come into contact with the stage and there's a small thumb-screw that can be used to tighten up the nose-piece for example during shipping. The objective lenses are as follows and all have appropriate storage canisters:
Standard objectives:
Lomo - 3.5x
CTS - 10x
CTS - 10x Apo
Lomo - 20x
CTS - 40x
CTS - 45x Fluorite - oil immersion - not tested with oil
CTS - 95x - oil immersion - not tested with oil
Phase Contrast Objectives:
CTS - 10x
CTS - 20x
CTS - 40x
CTS - 95x - oil immersion - not tested with oil
(The effective overall magnification therefore ranges from about 40x to 1,425x when using oil immersion with the 45x and 95x CTS lenses along with very 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's a CTS condenser in a height adjustable dovetail-fit mount with centering and an iris with graduated scale for controlling light levels, plus there's a 32mm swing out filter carrier for adding coloured, opaque or dark-field filters. As an alternative there's also a Phase Contrast condenser that fits into the same mount and can be swapped over in a few seconds. Phase Contrast is a more advanced microscopy technique usually used to discern greater detail/contrast in otherwise translucent biological specimens and is sometimes used in conjunction with coloured filters to further enhance contrast.
Sample illumination is provided via two complimentary options:
1) 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.
2) A base illuminator with flip in/out diffuser that can be fitted instead of the mirror unit. This also has: centering, a field iris operated by twist action and a flip in/out lens. This unit is now lit by a newly acquired low-voltage illuminator as shown in the final listing photo that plugs into the rear of the instrument.
Both lighting options work very well.
The overall condition of this technically capable, versatile and well-equipped M25 microscope is extremely good with no maintenance issues and it only has very minor signs of wear to the paint finish on the limb and base 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 and quite substantial hardwood research-grade storage case with this microscope with internal racking, carry-handle and working lock and key.
In summary, this is a fairly rare in such good condition example of the CTS M25 that's a well-equipped vintage technical binocular microscope from British optical firm CTS. Taken together the instrument, its accessories and the substantial storage case, 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 very good range of CTS/Lomo objective lenses, flexible lighting options 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 is very heavy and will be partially dismantled and very well packaged for transport. It will be dispatched by insured courier upon receipt of cleared funds. Overseas buyers please use eBay Global Shipping if it's available in your territory or contact seller.
Please study the photos as they also form part of the description.
Thanks for looking - please check out my other listings if you get the chance.