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Microscope setup references

  1. Nikon MicroscopyU. Microscope alignment for Köhler illumination. Conjugate planes, the filament image and illumination aperture.
  2. Evident Scientific. Köhler illumination. The six setup steps and an aperture near 80% of the objective opening.
  3. Evident Scientific. Immersion oil and refractive index. Cover glass and immersion oil at n ≈ 1.515.
  4. Leica Microsystems. Immersion objectives. Immersion, numerical aperture and resolving power.
  5. Nikon MicroscopyU. Microscope objective specifications. Objective magnification, numerical aperture and barrel markings.

The Meniscus DM-40 is a teaching instrument. Its 10×, 40× and 100× oil objectives use NA 0.25, 0.65 and 1.25. Resolution is the illustrative diffraction limit d = 0.61 × 0.55 µm ÷ NA. The dry 100× comparison uses an illustrative usable NA of 0.95. The ray angles follow Snell’s law.

The specimen-side close-up shows the cover glass, air or oil, and front lens. It omits condenser immersion and internal lens groups. The eyepiece uses one accepted normal-study cell photograph at three display scales. A full low-power field would contain many cells.

Read the film examination lesson. Its microscope setup reference is Rodak’s Hematology: Clinical Principles and Applications, 7th edition, Elsevier, 2025.