Kern OBN 148 fluorescence microscope, trinocular, 4x to 100x, HBO 100 W incident light, halogen transmitted light

The Kern OBN 148 is an upright fluorescence microscope with a trinocular head. It has two separate light sources: a 100 W HBO lamp for fluorescence in incident light and a dimmable 20 W Philips halogen lamp for transmitted light. Kern states that the instrument is intended for translucent, thin and low-contrast specimens, for example immunofluorescence, FISH or DAPI staining. Bright field in transmitted light is available for overview and routine work.

Fluorescence microscope with HBO incident light and filter wheel

The fluorescence unit excites the specimen using incident light. The filter wheel accommodates up to six filters; B, G, UV and V filters are fitted as standard. A centring objective is supplied for adjusting the fluorescence. Anyone who prefers LED excitation will find in the OBN 141 a fluorescence microscope with a 5 W LED and B and G filters. The OBN 148 additionally features UV and V filters and has a net weight of 16 kg, whilst the OBN 141 weighs 13 kg.

Objectives, eyepieces and tube

The nosepiece has five positions with Infinity Plan objectives: 4x/0.11, 10x/0.25, 20x/0.45, 40x/0.65 and 100x/1.25 for oil. The 20x, 40x and 100x objectives are spring-loaded; all five feature an anti-fungus design. The HWF-10x eyepieces have a 20 mm field of view, a high eye point and also feature an anti-fungus design. At the eyepiece, this results in a total magnification of 40x to 1,000x. The Siedentopf tube is inclined at 30 degrees and can be rotated through 360 degrees; the interpupillary distance ranges from 50 to 75 mm, and the dioptre adjustment operates on both sides from minus 5 to plus 5.

Köhler illumination, condenser and focusing

The transmitted light system features Köhler illumination with an adjustable field diaphragm. The 1.25 Abbe condenser can be centred and adjusted for height, and its aperture diaphragm is adjustable. A large mechanical stage supports the specimen. Coarse and fine focus are coaxial on both sides; the fine focus adjusts in steps of 0.002 mm. The field of view ranges from 0.2 to 5 mm, depending on the objective.

Camera and other contrast techniques

A C-Mount adapter is required to connect a camera to the trinocular output. This is not included in the scope of delivery. According to Kern, microscope cameras up to 8 MP are available for the OBN 148, as well as the cooled fluorescence camera ODC 861 and the tablet camera ODC 241. In addition to bright field and fluorescence, dark field, polarisation and phase contrast are provided as an option. They need additional accessories; the upgrade is done via the modular system.

Typical applications

Kern lists the following main areas of application for the OBN 148:

• Haematology, urology, gynaecology
• Dermatology and pathology
• Microbiology, parasitology and immunology
• Oncology and entomology
• Veterinary practices
• Water analysis and sewage treatment works
• Breweries

An immunofluorescence laboratory can first scan a stained specimen in bright field, set the region it is looking for and then switch to incident light with a fluorescence filter. Kern names DAPI staining as an application, and the filter wheel comes with a UV filter as standard.

Installation and connection

The unit measures 530 x 220 x 490 mm (W x D x H) and weighs approx. 16 kg net. The power supply is built-in and operates at 100 to 240 V; the power cable is detachable. According to the data sheet, the unit bears the CE mark. It may be stored at temperatures between -5 °C and +40 °C.

Regulatory information

As an electrical device, the microscope falls 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.

Frequently asked questions

Is a camera included in the scope of delivery? No. The trinocular output is prepared; camera and C-Mount adapter are ordered separately.

Can the transmitted light be dimmed? Yes, the 20 W halogen lamp is dimmable. According to the data sheet, only the transmitted light is dimmable.

Which fluorescence filters are included as standard? B, G, UV and V. The filter wheel accommodates up to six filters.

How long is the warranty? According to Kern & Sohn, this device comes with a 3-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.

Technical details

Scope of delivery

• OBN 148 fluorescence microscope with trinocular head
• Filter wheel with B, G, UV and V fluorescence filters
• Centring objective for fluorescence adjustment
• Power cable (IEC mains cable)
• Dust cover
• Eyecups
• Multilingual operating instructions

Not included are the camera and C-Mount adapter, as well as accessories for dark field, polarisation and phase contrast.

Individual requirements and procurement service

According to Kern, additional filters, eyepieces with a scale, objectives with higher colour correction, condensers for dark field and phase contrast, and a butterfly tube are available for the OBN 148. We will clarify which parts are compatible before you place your order. We source accessories and spare parts on request via our procurement service.