[5]: 100 The idea of widely separating the color correcting elements of a lens dates back to W. F. Hamilton's 1814 catadioptric Hamiltonian telescope and Alexander Rogers' 1828 proposals for a dialytic refractor.
[7] Dialyte designs were also used in the Schupmann medial telescope designed by in German optician Ludwig Schupmann near the end of the 19th century, in John Wall's 1999 "Zerochromat" retrofocally corrected dialytic refractor and the Russian made "TAL Apolar125" telescope which uses 6 elements arranged in three widely separated groups.
This consists of two air-spaced achromatic doublets arranged back-to-back around a central stop, or four air spaced lens elements in total: the outer pair is biconvex and the inner pair is biconcave; one example is the Celor.
The Swiss mathematician Emil von Höegh, who had designed the popular Dagor anastigmat lens for Goerz in 1892, continued to refine that design, resulting in the Goerz Dagor Type B lens of 1899, later renamed to Celor and Syntor.
[5]: 100 The Aviar lens (Taylor Hobson) designed by Arthur Warmisham (1917)[5]: 101 is similar but is considered to have a different origin, from the splitting of the central biconcave element of the Cooke triplet.