Enter the wavelength and the numerical aperture into the Calculator. The calculator will evaluate the Resolving Power from the Abbe Equation. 

Abbe Equation Formula

RP = w/(2*NA)


  • RP is the Resolving Power ()
  • W is the wavelength
  • NA is the numerical aperture

How to Calculate Abbe Equation?

The following steps outline how to calculate the Abbe Equation.

  1. First, determine the wavelength. 
  2. Next, determine the numerical aperture. 
  3. Next, gather the formula from above = RP = w/(2*NA).
  4. Finally, calculate the Resolving Power.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

wavelength = 1.25

numerical aperture = 23.4


What is the significance of the numerical aperture in optical systems?

Numerical aperture (NA) is a critical parameter in optical systems that measures the ability of a lens to gather light and resolve fine specimen detail at a fixed object distance. A higher NA indicates a greater ability to gather light and resolve finer details.

How does wavelength affect the resolving power of an optical system?

Wavelength plays a crucial role in determining the resolving power of an optical system. According to the Abbe equation, shorter wavelengths lead to higher resolving power, allowing the system to distinguish finer details in the specimen being observed.

Can the resolving power be improved without changing the numerical aperture or wavelength?

Improving the resolving power without altering the numerical aperture or wavelength is challenging. However, techniques such as using immersion oils between the specimen and the lens or employing advanced imaging techniques like structured illumination can effectively enhance resolution under specific conditions.

Why is the Abbe equation important in microscopy?

The Abbe equation is fundamental in microscopy as it quantitatively describes the relationship between the resolving power of an optical system, the wavelength of light used, and the numerical aperture of the system. This equation helps in designing optical systems with optimal resolution for various microscopy applications.