# Resolving Power of Microscopes and Telescopes

PhysicsOptics

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## Introduction

The resolving capacity of a particular instrument is very important as it allows the detailed analysis of a particular object. Resolution denotes the level of details that is observed by a microscope. It refers to the ability of a particular optical system to create distinguishable images of the objects which are separated by little angular distances. For microscope and telescope, the resolving power can be defined as the capacity of an optical instrument to recognize and distinguishes a certain distance between 2 objects.

## Resolving Power of Microscopes and Telescopes

The resolving power of a microscope and telescope refers to the ability to separate any object. There is an existing theoretical upper limit to the resolving power of optical patterns which is created by two closely placed objects. The resolving power of the optical instrument depends on the various matters.

## Limitation of the resolution

The limit of the resolution is the linear or angular distance between the two objects which are just resolved. It can be considered the same as resolving power. Therefore, an inferior value of the limitation to the resolution will mean a high resolving power of an objective lens.

Figure 1: Resolving power

## Resolving power of the Telescope

The telescope is a necessary instrument that is used to observe distant objects. It commonly consists of curved mirrors and lenses. The combination of these thighs helps to observe the distant objects when an individual looks through them. Various planetary objects are usually observed by it. The resolving power of the telescope is very important is very necessary as it helps to determine the distance between the two specific objects.

Figure 2: Resolving power of telescope

When particularly two distant stars remain close to one another, they affect a low angular separation (Verhoeven, 2018). The resolving power of the telescope is mentioned below-

"Resolving power" = "$\mathrm{1/\Delta \theta\: = \:d/1.22 \:\lambda}$"

$\mathrm{\Delta \theta}$ = "Angular separation between 2 objects that are just resolved"

d = "diameter of the lens"

$\mathrm{\lambda}$ = "wavelength of light"

Therefore, the telescopes, which hold a larger diameter or a larger "d", of lenses generally, possess a better quality of resolving power.

## Resolving the power of the microscope

The microscope is a particular instrument that is used to examine the microscopic specimens, which are very small to detect, by tube human eye. According to Granja et al. (2018), a microscope generally consists of two lenses i.e. ocular or eyepiece lens and an objective lens. Resolving power of the microscope is determined by the angle which is subtended by the diameter of the objective lens at the focus of the microscope and the refractive index of a particular medium between the microscopic specimens.

Resolving power of the microscope is mentioned below-

"Resolving power" = "1/$\Delta$d = 2a/$\mathrm{\lambda}$"

Where,

"A" indicates the "numerical aperture"

"λ" indicates "wavelength"

## Importance of resolving power of a microscope

The "resolving power" is one of the most vital features of an optical system that influences the capacity to distinguish between the fine details of a certain specimen (Leisawitz et al. 2019). All through high magnification with high resolution can enable observers to have a clear vision of the tiny microbes; it does not allow them to identify the difference between the "sub-cellular sections" of target microbes (Xu Wang & He, 2018).

Thus, microbiologists depend more on a resolution as it helps them to separate between microbes and their subsections. The resolving power of the microscope can be determined by the distinguishing capacity between two specific objects (Labiano et al. 2021). If anyone wants to observe the clear specimens in an optical microscope, then the minute features, which are present in the specimen, must be presented in a sufficient amount. It further helps in a god observation that is needed for a good quality of resolving power.

In the daily routine observation, many do not give the high image resolution. It is due to the fact that it does not have the "coherence of illumination", "aberration correction", types of the specimen, and some other factors. These factors are collectively responsible to give a high resolving capacity to a microscope.

## Importance of resolving power in the telescope

Resolving power in the telescope is determined by the ability to distinguish between two stars or two closely situated stars. The resolving power of the telescope allows for to collection and analysis of radiation from the celestial objects which are situated in the distant sky (Gatkine et al. 2021). A high resolution is needed for the correct evaluation of the two different objects. High resolving power is needed to appropriately measure the distance between two stars.

## Conclusion

The resolving power of the microscope and telescope are very necessary to correctly measure the distance between the two specific objects. A few factors affect the resolving power of the telescope and microscopes.

## FAQs

Q1. How resolving power of the telescope and microscope can be increased?

Ans. The resolving power will be increased by the diameter of the objective lens of the particular telescope. It is very essential to measure the space between two different objects.

Q2. What are the main factors that affect the resolving power of the microscope?

Ans. "Objective numerical aperture", types of specimen is some important factors that help to increase the resolving power of a microscope.

Q3. On which factors does the resolving power of the microscope depend?

Ans. It depends on the light wavelength ($\mathrm{\lambda}$) and numerical aperture (NA) of an objective lens. This is very important feature in measuring the resolving power of a microscope.

Q4. Which type of the microscope generally possesses "higher resolving power"?

Ans. Electron microscopes generally possess a "higher resolving power" than a light microscope. It is a very important feature of a microscope

Updated on 13-Oct-2022 11:19:47