# What is Angular resolution: Definition and 21 Discussions

Angular resolution describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution. It is used in optics applied to light waves, in antenna theory applied to radio waves, and in acoustics applied to sound waves. The closely related term spatial resolution refers to the precision of a measurement with respect to space, which is directly connected to angular resolution in imaging instruments. The Rayleigh criterion shows that the minimum angular spread that can be resolved by an image forming system is limited by diffraction to the ratio of the wavelength of the waves to the aperture width. For this reason, high resolution imaging systems such as astronomical telescopes, long distance telephoto camera lenses and radio telescopes have large apertures.

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1. ### I Is there a distinction between angular resolution and angular discrimination?

My understanding is that the terms are synonymous but I'm just wondering if there is a subtle difference between the two terms which I am unaware of.
2. ### B How to find inverse steradian from arcmin^-2 for density of galaxy

Hello, I am using a code on EUCLID future mission. The original author of this code has set a value for the density of galaxy equal to : ng = 354543085.80106884 I think this is expressed in inverse steradian. I think that EUCLID mission has a 30 arcmin^-2 value for density of galaxies...
3. ### Estimate the number of pixels in an image

Homework Statement The physical size of a single LOFAR station, operating at 150MHz is about 50m. Estimate the number of pixels which would be needed to map the full primary beam if one wished to include all LOFAR stations (maximum baseline ~ 800 km) at full resolution. Homework Equations...
4. ### I The 1.22 factor in the angular resolution

Hi. The angular resolution is calculated through $$\theta=1.22\frac{\lambda}{D}\enspace.$$ It's the first zero of the intensity function (in small-angle approximation) of the Airy disk...
5. ### How to find the minimum angular resolution?

Homework Statement λ = 240 nm D = 2.40 m We are supposed to find the angle resolution (minimum angular distance between two objects so we still see them as two separate objects) to the telescope for ultraviolet light with wavelength 240 nm Homework Equations The equation that I used is θ =...
6. ### B Color Dependence of Angular Resolution

Since, under rayleigh's criterion, the angular resolution is dependent on the wavelength of light, wouldn't blue light be more sharply focused by our eyes?
7. ### What's the relation between angular resolution and distance

Homework Statement At first I needed to calculate the angular resolution of a telescope (diameter 1m, for visible light) so I used θ=1.22λ/D and got 4.88x10^-7 rad. Now I am asked: "If we wished to use this telescope to image the moon, what is the closest distance two objects can be to be...
8. ### Angular resolution of microscope

Homework Statement Homework Equations θ =1.22λ/d The Attempt at a Solution for (a) θ =1.22λ/d θ =1.22(579nm)/(1.2cm)[/B] θ =5.8865x10^-5 degree= 1.027x10^-6 rad but the answer =2x10^-3rad , for the micorscope, the formula of angular resolution is different? i...
9. ### Black hole calculations, the "Event Horizon Telescope"

Homework Statement Soon astronomers will be imaging the “shadow” of light from the event horizons of black holes. Since black holes are very small, this achievement seems impossible. Nevertheless, it is possible for three reasons: 1. Supermassive black holes have large event horizons. 2. Radio...
10. ### Finding the angular resolution

Homework Statement Homework Equations θ=1.22 (λ/D) The Attempt at a Solution Just want to know if I properly answered this question. Thanks in advance
11. ### Finding the angular resolution of a telescope

Homework Statement An optical telescope has a diameter of 1.5m. It is placed at a site with 'seeing' of 1.0''. What is the expected resolution in arcseconds from observations made with the telescope at 1000nm? Give your answer to one decimal placeHomework Equations Theta (rads) = 1.22 *...
12. ### How Does Angular Resolution Differ from Other Types of Resolution?

The Wikipedia definition of angular resolution is 'Angular resolution, or spatial resolution, describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major...
13. ### Angular Resolution of Telescopes at 500nm: Formula & Explanation

Technological advances are now making it possible to link visible-light telescopes so that they can achieve the same angular resolution as a single telescope over 300 meters in size. What is the angular resolution (diffraction limit) of such a system of telescopes for observations at a...
14. ### Need Help Understanding Angular Resolution

When calculating angular resolution, is it correct that having a SMALLER number results in GREATER angular resolution? For example, is 26.25" better resolution than 2625"? Using the formula .25"(lambda in micrometre/diamter in meters), it would make sense to me that the larger the diameter...
15. ### Angular Resolution: Best Possible Observing Distance for Stars

Supposing a perfect optical instrument, what is the best angular resolution possible when observing distant stars?
16. ### Stargazing Spatial and Angular Resolution of a Earth observing Telescope

Does anybody know of a good reference for determining the required diameter of an Earth observing telescope's primary mirror? I am trying to find determine a rough estimate for a design I am working on. So far I have found the equation Sin\theta = 1.220 \lambda/D for angular resolution and...
17. ### Angular Resolution / Beam Width

Hello all, In terms of Radio Astronomy, can someone please explain to me the difference between the Beam Width and the Angular Resolution? I have a 1.2m dish to play about with, and I wanted to know what it could resolve. I thought I was sorted by using the diffraction formula, but then I...
18. ### What is the Angular Resolution Formula for the Hubble Space Telescope?

My main issue with this problem is the formula and how to derive it. Homework Statement The Hubble Space Telescope has a resolution of about 0.05 arc second. What is the smallest object it could see on the surface of the Moon? Give your answer in metres. Homework Equations I tried to...
19. ### How Is Angular Resolution Used to Determine the Distance Between Two Stars?

Homework Statement A radio telescope observes two stars orbiting each other, using radio waves of wavelength 20.0 cm. The stars are 10^7m away from the Earth. The telescope, which has a diameter of 20.0km, can just resolve the two stars. What is the distance between the two stars?Homework...
20. ### What is the spatial resolution of the eye for two red lights separated by 5cm?

Homework Statement Two red lights are separated by 5cm, perpendicular to your line of sight. How far away from them are you if they can just be resolved with the naked eye? Homework Equations angular resolution =sin(theta)=1.22lambda / D spatial resolution = 1.22(focal length * lambda)/D...
21. ### Deriving Angular Resolution from Bolometric Flux, Spectral Type & Temp

If we know the bolometric flux, spectral type, and effective temperature of a given star, how can we derive the angular resolution from the information? This was brought up in class and I've found myself obsessing since I can't figure it out.