Follows development and changes to Ronchi Testing methods.


Copyright Ė P. J. Smith

But permission is given to distribute this material in unaltered form as long as it is not sold for profit.



The main sources of information available to me were:-


(a)    A University Library with copies of JOSA, Applied Optics, Journal of Scientific Instruments.Unfortunately, these begin at approximately 1950 or even a little later.I know of no free source of this material apart from this library material.Any other references to this material would cost exorbitant fees to me.

(b)    ATM material in my possession.The ATM books 1, 2, and 3 span many of the years when the Ronchi test became known in the English speaking countries and was undergoing development.

(c)    The Scientific American columns.This is fertile ground, especially as this material has been republished on CD and is searchable.While this material is remarkable, it probably should be used with caution.Since it was primarily a commercial enterprise for popular science, it makes no pretence about rigorously providing references and acknowledgements.Often articles were published or topics simply allured to by the editor many years later.It is mainly a chat column that is unfortunately very much controlled by the editor and his close friends.Despite being extremely influential in the directions of Amateur Telescope Making in all countries, the outlook of the Editor of the column was decidedly insular with respect to much of the global optical industry.†† Despite this, one must recognise how seminal was this source of knowledge and communication to ATMís in general.Since many of these advanced ATMís were later transformed into professionals by the huge expansion of the optical industry due to wartime demand, this influence extended even further.

(d)    RAS publications, The Astrophysical Journal, etc.These have been grouped separately because they are all accessible via the NASA web document service.These are available free which is a service very much appreciated.Much of the early important work appears in these journals.

(e)    Material gained over the years from friends, books and experience that I simply can not now substantiate.

(f)      Direct experiments, measurements, and photographs etc. that have been undertaken over the last few years.



Despite any errors on my part, and a less than comprehensive review of the references below, I believe the material and conclusions presented in previous chapters to be substantially correct.


One thing that worries me about doing any research on Ronchi testing is the fact that in one article by Vasco Ronchi [1] in 1964 lists about 90 references relating to the Ronchi test of which I think 9 are in English.  I would like to follow his thoughts in the earlier articles but cannot either source or read them.  I suspect most of the English ones are abbreviated reports.


A simple comprehensive list of references will be found under References.


For convenience, this history has been loosely split up into the following eras.

They are somewhat arbitrary but I do believe the arrangement is reasonably logical.

††††††††††††††† Before 1920 - before Ronchi.


††††††††††††††† 1920 - 1924-the Beginnings.


††††††††††††††† 1924 - 1928-immediate Responses.


††††††††††††††† 1929 - 1938-theU.S.Connection.


††††††††††††††† 1938 - 1945-Turmoil.


††††† ††††††††††1946 - 1970-†† Rigour and Expansion.


††††††††††††††† 1970 - 2000-†† New Ideas.



[1] 1964. V. Ronchi. Appl. Opt. 3, 437, (1964).††† "Forty Years of History of a Grating Interferometer"This is a Ďmust readí reference for anyone interested in Ronchi Testing.