Kern OBT 102 transmitted-light microscope, monocular, 40x to 400x, 1 W LED

The Kern OBT-1 is a range of six transmitted-light microscopes designed for teaching, training and hobby use. Kern refers to them as school microscopes. All models feature a continuously dimmable 1 W LED, achromatic objectives, a WF 10x eyepiece with an 18 mm field of view, and a tube that is tilted at 45° and rotates through 360°. The models differ in terms of the tube (monocular or binocular), the condenser, the number of objectives and whether a mechanical stage is included.

Which model for which application

The OBT 101 is the most basic model. It has three objectives (4x, 10x, 40x), a simple condenser with an aperture of 0.65 and a three-position nosepiece. The OBT 102 has the same optics, but features an Abbe condenser with an aperture of 1.25 and a four-position nosepiece. The OBT 103 also features a mechanical stage, which allows the specimen to be moved. The OBT 104 is identical to the OBT 103, but has a binocular tube for viewing with both eyes. The OBT 105 is monocular and has a 100x objective for oil immersion fitted at the factory. The OBT 106 is equipped in the same way as the OBT 105, but has a binocular tube. For the OBT 101 to OBT 104, the 100x objective is available as an accessory (OBB-A3207). Standard objectives are sufficient for general observation up to 400x.

Optics and magnification

The objectives are achromatic: 4x with an aperture of 0.1, 10x with 0.25 and 40x with 0.65. The 40x objective is spring-loaded, meaning it moves upwards when placed on the specimen. Only the OBT 105 and OBT 106 come factory-fitted with a 100x objective with an aperture of 1.25 for oil immersion, which is also spring-loaded. With the 10x eyepiece, this results in a total magnification of 40x to 400x; for the OBT 105 and OBT 106, this extends up to 1,000x. According to the data sheet, the field of view measures 0.45 to 4.5 mm. The eyepieces have a field of view of 18 mm and a mounting diameter of 23.2 mm; according to the data sheet, they are fixed. On the OBT 104 and OBT 106 binocular models, the interpupillary distance can be adjusted from 48 to 75 mm; the dioptre adjustment operates on one side only from -5 to +5.

Illumination and condenser

The light comes from below via a 1 W LED, which can be dimmed continuously. The OBT 101 has a simple condenser with an aperture of 0.65 and an aperture diaphragm. In the OBT 102 to 106 models, an Abbe condenser with an aperture of 1.25 and an aperture diaphragm is permanently fitted inside the unit and can be adjusted vertically. Colour filters in grey, green, yellow and blue are available as accessories; the data sheet lists these filters as options.

Focusing and power supply

Focus is adjusted via a coaxial coarse and fine focus control that can be operated from either side; the fine focus control adjusts in increments of 0.0025 mm. The microscope is powered by a plug-in mains adaptor rated for 100 to 240 V; the unit receives 5 V at 1,000 mA. It is also designed for battery operation; the batteries are not included in the scope of delivery. Kern names mobile use as the purpose. The dimensions are 195 x 147 x 325 mm, and it weighs approximately 2.8 kg.

Typical applications

• Primary and secondary schools: observing plant tissue and cells in biology lessons
• Training: introduction to microscopy using stained specimens
• Hobby: observing thin, high-contrast specimens
• Camera documentation: eyepiece cameras are also available for the OBT 104, OBT 105 and OBT 106

Kern lists translucent, thin and high-contrast specimens as examples, such as plant tissue or stained cells and parasites. According to the data sheet, the contrast method is bright field.

Models at a glance

Technical details

These values apply to all models. Any differing values are listed in the model table.

Scope of delivery

• Microscope OBT 101, OBT 102, OBT 103, OBT 104, OBT 105 or OBT 106, depending on the model
• WF 10x eyepiece (OBT 104 and OBT 106: two eyepieces)
• Achromatic objectives 4x, 10x, 40x (OBT 105 and OBT 106: plus 100x)
• Plug-in mains adaptor with Euro plug
• Dust cover
• Operating instructions

Warranty

According to Kern & Sohn, these microscopes come with a 2-year warranty. Kern grants 3 years on products with a list price of €500 or more and 2 years on products below that and on components; wear parts such as batteries and rechargeable batteries are excluded. Warranty repairs are carried out by Kern or by a Kern dealer.

Downloads

• Operating instructions Kern OBT-1 (PDF)

Regulatory information

As electrical devices, the microscopes fall under the ElektroG. The manufacturer Kern & Sohn GmbH is registered under the WEEE registration number DE 80821200. How to return old appliances is described on the page Environment and disposal.

Individual requirements and procurement service

Eyepieces OBB-A3201 (WF 10x) and OBB-A3202 (WF 10x with 0.1 mm scale), the OBB-A3206 objective (60x, aperture 0.85, spring-loaded), for OBT 101 to OBT 104 the OBB-A3207 objective (100x, aperture 1.25, oil, spring-loaded), the colour filters OBB-A3209 (grey), OBB-A3210 (green), OBB-A3211 (yellow) and OBB-A3212 (blue); for OBT 101 and OBT 102, the specimen holder OBB-A3217 (clip), the cleaning spray OCS-A1101, the cleaning kit OCS 901 and the microscope camera ODC 231 (2 MP, USB 2.0, MicroSD) are also available. The ODC 874 (3.1 MP, USB 2.0) and ODC 881 (5.1 MP, USB 3.0) eyepiece cameras are also available for the OBT 104, OBT 105 and OBT 106. Enquiries are handled via our procurement service.