Angular resolution

Angular resolution is using image-forming device to get small details of an object. This can increase the image resolution of the image. It is used in optical or radio telescopes, microscopes, cameras, and eyes. In optics, it is used for light waves. In antenna theory, it is used for radio waves. In acoustics, it is used for sound waves.

Images that show M87* with an angular size of some microarcseconds. It is compared to seeing a tennis ball on the Moon

An optical system can have a high angular resolution. This means that the perceived angular distance, (or what the viewer thinks the angular distance is) or the actual angular distance between the objects is small.

θ is the amount of angular resolution. An angular resolution can be found from the Rayleigh criterion.

Telescopes and angular resolution

Name	Image	Angular resolution (arc seconds)	Wavelength	Type	Site	Year
Global mm-VLBI Array (successor to the Coordinated Millimeter VLBI Array)		0.000012 (12 μas)	radio (at 1.3 cm)	very long baseline interferometry array of different radio telescopes	a range of locations on Earth and in space[1]	2002 -
Very Large Telescope/PIONIER		0.001 (1 mas)	light (1-2 micrometre)[2]	largest optical array of 4 reflecting telescopes	Paranal Observatory, Antofagasta Region, Chile	2002/2010 -
Hubble Space Telescope		0.04	light (near 500 nm)[3]	space telescope	Earth orbit	1990 -
James Webb Space Telescope		0.1[4]	infrared (at 2000 nm)[5]	space telescope	Sun–Earth L2	2022 -

Related pages

• Angular diameter
• Visual acuity