Meopta A26Bi
is a simple microscope primarily used in schools and universities due to its easy operation. Basically, it allows the user to observe the specimen in the light field and, with the use of a filter, also in the dark field.
This A-series microscope (and also the B-series microscopes) was produced in several variants. The first number indicated the type of condenser, the second the shape of the stage, and the letter marking encoded the type of tube/head.
(A)1X- carried a simple Abbe condenser with uniform aperture
(A)2X- had a 1.4NA Abbe condenser with a detachable upper optic, which could be used for low magnification, in addition this condenser had a slot for filters
(A)3X- it was a modified condenser from the (A)2x series, but it had the possibility to align and rotate the optical assembly together with the aperture, which allowed to use the oblique illumination method. and better center the condenser for Köhler illumination
(A)X1 - had a simple fixed round table with a pair of spring-loaded slide holders
(A)X3- advanced round table with the possibility of lateral movement (+-10mm) using centering screws, slide held again by a pair of spring-loaded slide holders
(A)X5- this is a modified table from the (A)X3 series, but the slide was guided by a micrometer cross slider
(A)X6- large square table with micrometric displacement
(A)XX P - fixed tube of uniform length
(A)XX V - telescopic monocular tube with the possibility of adjusting the distance 160 - 190 mm according to the optics used (PZO 160 mm, Meopta 170 mm, Zeiss 160 mm, Lomo 160 mm)
(A)XX Bi - binocular head with 1.5x prism magnification
(A)XX S - fixed-length monocular angled head with 1.3x prism magnification
(A)XX SV - adjustable length monocular angled head with 1.3x prism magnification (the angled tube can be seen on the Meopta BC28 SV field microscope
Under the table is an Abbe condenser with a numerical aperture of 1.4 NA. It allows you to remove the top lens and lower its aperture (0.45NA) for weak lenses (low magnification). This condenser as mentioned has a mount for traditional 32mm filters.
The basic optical equipment of the Meopta A26Bi microscope are achromatic objectives with magnifications of 10, 20, 45 and 100×. In addition to the set shown, achromatic objectives of 3; 6 and 30× could also be used. For these microscopes it was also possible to combine optics from other manufacturers, for example from the Polish company PZO, as shown in the photo (PZO achromat 5/0,12NA.
In addition to the supplied Huygens eyepieces H6, H8 and H10×, it was possible to use periplanatic eyepieces P10, P15, P20 or orthoperiplanatic eyepieces with a large field of view O10, O15 or O20×.
In addition to conventional eyepieces, the H8 eyepiece could also be used, which was supplemented with an imaging needle for easy depiction of the specific feature observed in the slide. Meopta also produced a micrometer eyepiece, marked as 015×, which allowed precise measurement of the specimens.
The photographs shown above correspond to the A26 Bi, as the microscope has a binocular head. For use with the camera, an adjustable monocular tube had to be fitted to the microscope. This turned the microscope into the A26 V series. A clamp reduction was fitted to this tube, which allowed the use of Meopta FU projection eyepieces (2.5; 4; 6.3×) and a direct reduction or inspection eyepiece together with the camera.
