Physics:Dawes' limit
From HandWiki
Dawes' limit is a formula to express the maximum resolving power of a microscope or telescope.[1] It is so named after its discoverer, William Rutter Dawes ,[2] 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) |
| R is the resolving power of the instrument |
This formula agrees with the usual [math]\displaystyle{ R = 1.22 \lambda/D }[/math] at a wavelength of about 460nm, somewhat bluer than the peak sensitivity of rod cells at c. 498nm.
See also
- Rayleigh criterion
References
- ↑ Bob King (2017-03-01). "Pushing Limits: A Spring Sky Double Star Romp". Sky and Telescope magazine. https://www.skyandtelescope.com/observing/pushing-limits-a-spring-sky-double-star-romp/. Retrieved 2020-02-12. "The most stringent test of telescopic resolution uses the criteria of Dawes' limit given by the equation R = 4.56/D, where R is the resolution in arcseconds and D is the telescope's aperture in inches."
- ↑ Dawes, W.R., Catalogue of Micrometrical Measurements of Double Stars. In: Memoirs of the Royal Astronomical Society, Vol. 35, p.137 1867, Bibcode: 1867MmRAS..35..137D
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