Specific cases

Single telescope

Point-like sources afar by an bend abate than the angular resolution cannot be resolved. A individual optical telescope may accept an angular resolution beneath than one arcsecond, but ample seeing and added atmospheric furnishings accomplish attaining this actual hard.

The angular resolution R of a telescope can usually be approximated by

R = \frac {\lambda}{D}

where

λ is the amicableness of the empiric radiation

and D is the bore of the telescope's objective.

Resulting R is in radians. Sources beyond than the angular resolution are alleged continued sources or broadcast sources, and abate sources are alleged point sources.

For example, in the case of chicken ablaze with a amicableness of 580 nm, for a resolution of 0.1 arc second, we charge D = 1.2 m.

This formula, for ablaze with a amicableness of about 562 nm, is aswell alleged the Dawes' limit.

edit Telescope array

The accomplished angular resolutions can be accomplished by arrays of telescopes alleged ample interferometers: These instruments can accomplish angular resolutions of 0.001 arcsecond at optical wavelengths, and abundant college resolutions at radio wavelengths. In adjustment to accomplish breach amalgam imaging, a ample amount of telescopes are appropriate laid out in a 2-dimensional arrangement.

The angular resolution R of an interferometer arrangement can usually be approximated by

R = \frac {\lambda}{B}

where

λ is the amicableness of the empiric radiation

and B is the breadth of the best concrete break of the telescopes in the array, alleged the baseline.

The consistent R is in radians. Sources beyond than the angular resolution are alleged continued sources or broadcast sources, and abate sources are alleged point sources.

For example, in adjustment to anatomy an angel in chicken ablaze with a amicableness of 580 nm, for a resolution of 1 milli-arcsecond, we charge telescopes laid out in an arrangement that is 120 m × 120 m.