Dawes limit
Encyclopedia
Dawes' limit is a formula to express the maximum resolving power
of a microscope
or telescope
. It is so named for its discoverer, W. R. Dawes, although it is also credited to Lord Rayleigh.
The formula takes different forms depending on the units.
Angular resolution
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...
of a microscope
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
or telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
. It is so named for its discoverer, W. R. Dawes, although it is also credited to Lord Rayleigh.
The formula takes different forms depending on the units.
| R = 4.56/D | D in inches, R in arcseconds |
| R = 11.6/D | D in centimeters, R in arcseconds |
| where | D is the diameter of the main lens (aperture Aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,... ) |
| R is the resolving power of the instrument |