NavList:

Hello all,

As I was reading about the ARG-1 sight reduction optical/mechanical device in David Charlwood's article (On the Astronomisches Rechengerat ARG1, The Navigator’s Newsletter, Issue 76, Summer 2002), I noticed the requirements laid down for such a device, between which:

• The solution of the spherical triangle must be so simplified that, ..., will be shown directly, without intermediate quantities and without rules ..., within an accuracy of about +/- 1' of altitude and +/- 1° of azimuth
• It should be suitable for use in all latitudes and for all heavenly bodies

Later in the text I stumbled upon this phrase: "Comparative trials were conducted by the German Hydrographic Institute at Hamburg in the 1940's between the ARG1 and the S-Diagrams developed by K. Shutte". By this I assume that the S-Diagrams had been considered by Luftwaffe at least as a comparable option for a quick and relatively accurate sight reduction method.

Intrigued by the above, I searched this forum and the web to get more info about the diagrams. However, I have found nothing more than an article by K. Shutte himself (S-Diagrams for Solving Problems in Astronomical Navigation, The Journal of Navigation, Vol. 8, Issue 4, October 1955) and another one by W. M. Smart with an explanation of the mathematics behind the method (S-Diagrams for Solving Problems in Astronomical Navigation, The Journal of Navigation, Vol. 9, Issue 3, July 1956). Although the latter is freely accessible and provides some insight into the inner workings of the method, unfortunately the former isn’t free at all. Reluctant as I am to pay 30 quid to have access to the text, I am wondering if anyone has heard of the S-Diagrams, their history, any limitations they may have, where they were published, if they actually meet the above-mentioned requirements, if they can be found under some other name, etc.

Cheers,

Michalis Vaidanis