Астрономия и микроскопия

I have done some more testing and some thinking about why the image quality was so poor when the condenser was oiled and the aperture was set to fill about 80% of the rear element of the 90X objective. I believe that the poor image quality is the result of oiling the condenser. The image quality is good when the condenser is dry. Köhler illumination can then be achieved with the 90X objective, but only with a dry condenser.

The best illumination is with a 245 mm distance from the collector lens to the condenser with about 0.70 mm air gap under the slide to the top of the condenser. If you think about what happens, if there is a significant gap you will see how the spherical aberration of the illumination system would be drastically increased when this gap is filled with oil. The condenser is claimed to be aplanatic. I maintain that it is aplanatic at high NA, but only when used dry.

The LOMO information indicates that the condenser is expected to normally be used dry. The claimed 1.40 NA can only be achieved when the air gap below the slide is filled with oil, but then the image quality is ruined by the spherical aberration in the illumination caused by oiling the condenser. I believe that this illumination with an oiled condenser will be very useful for darkfield using the water immersion 30X objective without a cover glass.

ОИ-14:расчитан на работу когда от линзы до объекта 1.25-1.4мм и расстояние до полевой 210мм.

Нет. не поможет, диафрагмируют объектив когда его апертура равна или выше апертуры ТП освещения. А вот когда поле освещения меньше поля зрения тогда поможет только замена конденсора который имеет большее освещаемое поле.

Я кстати думал что высота от опорной плоскости до верхней поверхности у них стандартизована, иначе ведь либо "недолёт" будет, либо в предметное стекло врежется...

Если не лень, проверьте на КФ-4.

Köhler/Critical illumination setup rules dictate illumination methodology, and in particular the one which advises us to focus the substage condenser on the leaf edges of the lamphouse condenser's iris diaphragm. The simple fact is that the Abbe is not capable of providing all objectives with the full light cones they require with this singular setting of the substage condenser. Whilst owners of the achromat/aplanat condensers can leave their condensers sharply focussed on their lamphouse diaphragms, and know that the geometry of the condenser's source imagery will fully illuminate all their objective's apertures, subject to modification with the condenser's iris, those who use the Abbe should take this dictum in the Köhler setting up procedure only as a guide: a starting point.

Instead we simply elevate the Abbe to make sure the higher NA cone optimises the filling of the objective's back lens. This is necessary when we employ a high NA objective. The first image below left shows the field restricted by the lamphouse iris as per Köhler setup. When the higher NA cone of the Abbe is brought onto the specimen by raising it a little we will bring about an image similar to that shown below on the right.