formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
to express the maximum resolving power of a microscope or telescope. It is so named after its discoverer, W. R. Dawes
,Dawes, W.R., ''Catalogue of Micrometrical Measurements of Double Stars.''
In: Memoirs of the Royal Astronomical Society, Vol. 35, p.137 1867, although it is also credited to Lord Rayleigh.
The formula takes different forms depending on the units.