This is description of this part:
Wild Heerbrugg 20x microscope objective from the Wild M20 microscope
Manufacturer: Wild Heerbrugg, Switzerland
Model: Fluotar 20 0.60
Magnification: 20x
Correction: Fluotar (other names: Fluor and fluorite)
Numerical aperture N.A.: 0.60
Tube length: 160 mm
Parfocal length: 33 mm
Cover glass: yes, 0.17 mm thick
Immersion: no (dry objective)
Thread: RMS
The objective comes in its original protective case marked "Wild Heerbrugg Switzerland".
Fluotar is the name Wild Heerbrugg used for its fluorite objectives, i.e. semi-apochromats - their lenses contain fluorite or glass with similar optical properties. A standard achromat corrects chromatic errors for only two colors (red and blue), so colored fringes may appear along the edges of objects. An apochromat corrects for three colors (red, green and blue) and represents the highest class of correction. The Fluotar sits between them - colored fringes are clearly smaller than with an achromat, although the correction is not as complete as with an apochromat. Fluorite also transmits ultraviolet light well, which is why objectives of this type were used in fluorescence microscopy.
This is a so-called "short barrel" objective with a parfocal length of 33 mm. It is very common to mount this objective on a 12 mm extension, which allows it to be used in microscopes that require 45 mm parfocal objectives. Professional adapters with protective optics, metal adapters and popular DIY 3D-printed adapters all work well for this.
This objective fits practically any microscope from any manufacturer, as long as it has an RMS thread and accepts objectives with TL=160 mm and a parfocal length of 33 mm (or 37 / 45 mm with a suitable adapter). Several example microscopes are listed in the "compatibility" section, but the list is not complete.
What is this part needed for?
- If you have a Wild Heerbrugg microscope without objectives and want to complete it with original parts
- If your microscope lacks an objective of this magnification and you want to add one
- If you have an objective of this magnification, but it is an achromat - and you want a visibly better image
- If you have such an objective, but it is of very poor quality or damaged
- If you like to be prepared and want to keep such an objective as a spare
- If you want to use this objective on other compatible microscopes
