Cover Glass Thickness 1
Cover Glasses Thickness 1 from Marienfeld
For covering microscopic specimens on microscope slides
Cover glasses of thickness no. 1 are standardized to a thickness of 0.17 mm with a refractive index of 1.5255. The thickness of the cover glass must be considered when designing the microscope objective; otherwise, image quality may be compromised.
However, objectives with a numerical aperture up to 0.30 can typically be used with or without a cover glass. Oil immersion objectives can even reach a numerical aperture of up to 1.25.
The numerical aperture refers to the measure of a lens's ability to gather light and resolve fine details.